"We are extremely worried that some countries confident of their military power are turning Syria into a scene for arm wrestling," Erdogan said in a speech in Ankara after Washington and Moscow traded accusations.

His comments came after US President Donald Trump warned Moscow on Wednesday that US missiles "will be coming" to Syria in retaliation for an alleged chemical weapons attack in Syria which reportedly killed dozens.

Erdogan said he would talk to Russian President Vladimir Putin about "how we stop this chemical massacre" after the suspected attack.

A Turkish presidential source later confirmed the call had taken place but said only that the two men "exchanged views on the latest developments in Syria" and agreed to maintain contact.

Ankara appears keen to keep its distance from one of the worst outbreaks of tensions since the Cold War between its NATO ally Washington and increasingly close partner Moscow.

Erdogan's comments echoed those of his Prime Minister Binali Yildirim who called on Russia and the United States on Wednesday to stop "street fighting" on Syria.

- 'Assad's black mark' -

While Russia, alongside Iran, has been supporting the regime of Syrian President Bashar al-Assad, Turkey has repeatedly called for his ouster and supported Syrian rebels.

But Turkey and Russia in recent months have put their differences aside and have been working closely to find a political solution to the conflict.

Last week, Putin and Iranian President Hassan Rouhani were hosted by Erdogan in Ankara for a tripartite summit to discuss the Syrian conflict.

The alleged chemical attack in rebel-held Douma near Damascus on April 7 sparked international outrage and warnings of possible military action.

Turkey's foreign ministry has said it strongly suspects Assad was to blame.

"God willing, the (world's) collective conscience will act together to end this crisis for th sake of the innocent children massacred in the chemical attack in Douma," Erdogan vowed.

Erdogan said the Assad regime already had "a black mark on its track record" after seven years of civil war in Syria.

Without naming the countries, he appeared to lash out both at Russia for backing Assad and the United States for helping the Syrian Kurdish group the Democratic Union Party (PYD), which Turkey considers a terror group.

"Those who support the regime of murderer Assad are making a mistake. Those who support the PYD terror group are also making a mistake. Until the end, we will fight against both these mistakes."