Turkey has launched a military operation in northeast Syria. President Recep Tayyip Erdogan said the offensive, which began with air raids on Tuesday, is aimed at removing Kurdish-led forces from the border area and creating a "safe zone" to which millions of Syrian refugees can be returned.
Special Aide on International Affairs of the Islamic Parliament, Hossein Amirabdollahian, warned that the Turkish operation in Syria further complicates situation and threatens regional security.
Amirabdollahian added in a tweet on Wednesday that mutually honoring territorial integrity, negotiations and agreement are the solutions to border security.
He further warned crisis intensification, new wave of refugees and terrorism surge care the consequences of military campaign.
Iran's parliamentary Speaker Ali Larijani cancelled his scheduled trip to Turkey after Ankara launched its military operation, Iranian state TV reported.
"Larijani was invited by his Turkish counterpart to attend a parliamentary meeting in Turkey. His trip has been cancelled," state television said, without providing further details.
Kuwait said the Turkish offensive was a direct threat to stability and peace in the region and called for restraint, state news agency KUNA reported.
For his part, the UAE foreign ministry condemned the Turkish offensive in a statement carried by the state news agency WAM.
The ministry's statement said that the Turkish aggression represents a dangerous development and a blatant and unacceptable move against the sovereignty of an Arab state in contravention of the rules of international law.
Egypt's Foreign Ministry slammed Turkey's military operation, calling it an "aggression" against Syria's sovereignty.
In a statement, the ministry condemned "in the strongest words" the offensive and called for the UN Security Council to halt "any attempts to occupy Syrian territories" or "change the demographics in northern Syria".
It also called for an emergency meeting of the Arab League.
Saudi Arabia's foreign ministry denounced Turkey's military push as a "blatant violation of the unity, independence and sovereignty of Syrian territories".
In a series of posts on Twitter, the ministry said Riyadh "expressed its concern over this aggression as a threat to regional peace and security".
The Arab League said foreign ministers from around the region will meet to discuss Turkey's military operation in Syria.
Hossam Zaki, deputy secretary-general of the pan-Arab organization, said the meeting will take place in the Egyptian capital Cairo on Saturday.
The head of the Arab League said he was alarmed at Turkey's planned military offensive into northeastern Syria.
In a statement on Wednesday, Ahmed Aboul Gheit said that such an invasion would be a "blatant violation of Syria's sovereignty and threatens Syria's integrity".
He added that Turkey's planned incursion also threatened to inflame further conflicts in eastern and northern Syria, and "could allow for the revival" of the Islamic State of Iraq and the Levant (ISIL, also known as ISIS) armed group.
US President Donald Trump said he would devastate Turkey's economy if its offensive in Syria wipes out the Kurdish population there.
Asked by a reporter if he was concerned Erdogan will wipe out the Kurds, Trump replied: "I will wipe out his economy if that happens."
"I've already done it once with Pastor Brunson," Trump said, referring to US sanctions slapped on Turkey over the detention of a US citizen.
"I hope that he will act rationally," he added.
Trump also warned Turkey against attacking Syria, saying its air assault was "a bad idea" not backed by the United States, and called on Ankara to protect religious minorities.
"The United States does not endorse this attack and has made it clear to Turkey that this operation is a bad idea," Trump said in a statement released by the White House.
"Turkey has committed to protecting civilians, protecting religious minorities, including Christians, and ensuring no humanitarian crisis takes place - and we will hold them to this commitment."
US Secretary of State, Mike Pompeo, said Washington did not give Ankara "a green light" for a military offensive into Syria.
"That's just false," Pompeo said, in an interview with PBS channel, but did not elaborate other than to say that Turkey has a "legitimate security concern".
"They have a terrorist threat to their south... We’ve been working to make sure that we did what we could do to prevent that terror threat from striking the people in Turkey, while trying to achieve what is in America’s best interest: the threat from radical Islamic terrorism emanating from Syria." H added.
Pompeo further affirmed that the US is leaving Syria because it has achieved the goal of eliminating the Islamic State's territorial hold, which the Kurdish-led Syrian Democratic Forces played an instrumental part in.
"We'll continue to be in a position to do what we need to do to keep the American people as safe as we possibly can from this threat," the Secretary of State said.
UN spokesperson said “the Secretary-General is very concerned by the recent developments in northeast Syria,” adding that “any military operation must fully respect the UN Charter and international humanitarian law.”
Reading from a statement, UN Deputy Spokesperson Farhan Haq told reporters on Thursday that the UN chief believes “there is no military solution to the Syrian conflict,” and reiterated that “only an inclusive and credible political process pursuant to Security Council resolution 2254 (2015) can bring a long-term solution to the conflict in Syria.”
Haq continued “as the Security Council reaffirmed yesterday (08 Oct) in its Presidential statement, any solution must respect the sovereignty and territorial integrity of Syria.”
On humanitarian front, Haq said “the UN does not have an alternative form of delivery that could replicate the timely and its reach of its cross-broader activities, particularly as the access to the northwestern Syria for humanitarian partners registered at Damascus was restricted.”
He reiterated it remains “critical to fully preserve all possible avenues for humanitarian access.”
Australian Prime Minister Scott Morrison said on Thursday he had been in contact with the Turkish and US governments overnight, but admitted to being worried about the situation in Syria following Ankara's announcement of a military operation.
"We are very concerned about what this could potentially mean for the Kurdish people," he said. "We're concerned about what this could mean for the potential for the resurgence of Daesh," he added.
British Foreign Secretary Dominic Raab said he had "serious concerns" about Turkey's military push.
"This risks destabilizing the region, exacerbating humanitarian suffering, and undermining the progress made against Daesh [ISIL] which should be our collective focus," Raab said in a statement.
"Turkey has shown considerable generosity in hosting so many Syrian refugees. But we will not support plans for returns until the conditions are in place for a voluntary and safe return home," he added.
Dutch Foreign Minister Stef Blok said he had summoned the Turkish ambassador after Ankara launched the military offensive in Syria.
"The Netherlands condemns the Turkish offensive in northeast Syria," Blok said in a statement. "We call on Turkey not to continue on the path they are going down."
Turkey "is willingly risking further destabilizing the region and a resurgence of IS [ISIL]" by attacking northeastern Syria, German Foreign Minister Heiko Maas said.
"Syria needs stability and a political process... however, the Turkish offensive now threatens to cause a new humanitarian disaster," Maas said in a statement, adding that Berlin would "urge Turkey to end its offensive and to pursue its security interests peacefully".
NATO Secretary-General Jens Stoltenberg said Turkey should act with "restraint" and any military action taken should be "proportionate", adding that it was important not to destabilize the region any further.
Stoltenberg told reporters that Turkey had "legitimate security concerns" and had informed NATO about its planned offensive earlier in the day.
"I count on Turkey to act with restraint and ensure that any action it may take in northern Syria is proportionate and measured," he said, after meeting Italian Prime Minister Giuseppe Conte. "It is important to avoid actions that may further destabilize the region, escalate tensions and cause more human suffering."
European Commission President Jean-Claude Juncker urged Turkey to halt its military operation and warned the European Union would not help finance the creation of any "safe zone" in northeastern Syria.
"I call on Turkey as well as on the other actors to act with restraint and to stop operations already, as we are speaking, underway," Juncker told EU legislators.
French President Emmanuel Macron is very worried at the prospect of a Turkish army operation into areas controlled by Kurdish forces in northern Syria, his office said.
Macron met senior Syrian Kurdish official Ilham Ahmed at the Elysee Palace on Monday "to show that France stands alongside the SDF as they are partners in the fight against ISIL and that we are very worried by the possibility of a Turkish operation in Syria," a presidential aide told AFP.
The aide added that Paris would "pass on these messages" to the Turkish authorities.
Russia's Foreign Minister Sergey Lavrov said as Turkish forces prepared to enter the country Syria's territorial integrity must be preserved.
"Americans have violated their promises many times," Lavrov said, adding that the US was playing "a very dangerous game".
The foreign minister also discussed the issue with Kurdish leaders in Iraq.
"They are extremely alarmed that such a lightweight treatment of this extremely delicate subject could ignite the entire region," he said.