Turkey urged Iran Tuesday to pressure Syria's regime to stop violence against its own people, as Turkish premier Recep Tayyip Erdogan brushed off Iranian criticism of Ankara's plans to deploy Patriot missiles as "random remarks".

Tensions between Iran and Turkey have spiked in the wake of NATO's decision to deploy the US-made missiles along the Turkish-Syrian border in case of an attack emanating from Syria.

Turkish Foreign Minister Ahmet Davutoglu waded into the diplomatic melee Tuesday, urging Tehran to focus its energies on sending "clear messages" to the Syrian regime rather than protesting the missile deployment.

"Instead of criticising the (Patriot missile) system, Iran should say stop to the Syrian regime that has been continuously oppressing its own people and provoking Turkey through border violations," Davutoglu told reporters in Ankara.

"Today if there is an element in the region that threatens peace, it is the Syrian regime's aggressive policies.

"What we expect from Iran is not to make statements on the deployment of a defensive system but to use its leverage and give very clear messages in order to make sure that the oppression stops."

His comments came after Iranian political and military officials sharply criticised NATO and Turkey over the Patriot missile decision.

Iranian Foreign Minister Ali Akbar Salehi called the planned deployment "provocative" and said it could bring about "uncalculated" results.

And Iran's military chief of staff, General Hassan Firouzabadi, on Saturday warned Turkey the move was part of a Western plot to "create a world war".

Prime Minister Erdogan scorned that remark Tuesday, saying the chief was "known for such random remarks".

"When we ask (Iranian) authorities about that, they say his views are 'entirely his own'," he told reporters. "That's some mentality there (in Iran)."

Turkey has turned to its NATO allies for the deployment of Patriot missiles along its border after a series of cross-border shellings, including one in October which killed five Turks.

NATO chief Anders Fogh Rasmussen on Monday denounced the claims by the head of Iran's armed forces and said: "We are there to defend and protect Turkey. We have no offensive intention whatsoever."

Turkey also insists the system is purely defensive.

"Those who closely follow the issue are aware that the Patriot system is for defence and will not operate unless there is any attack (targeting Turkey)," the foreign minister said.

But both Russia and Iran, the most powerful allies of Syrian President Bashar al-Assad, oppose to the move, fearing it could spark broader conflict.

Germany, the Netherlands and the United States have agreed to provide the missile batteries, which would come under NATO command.

On Tuesday, around 40 German officers were surveying possible sites in Turkey's southeast for the deployment.

Relations between Iran and Turkey, a fierce critic of the Damascus regime, have been strained over the 21-month conflict in Syria.

Some Iranian officials have accused Turkey of arming Syrian rebels, charges repeatedly rejected by Ankara.

Iranian President Mahmoud Ahmadinejad cancelled a planned Monday visit to Turkey "because of a busy schedule", his office said. He was to have met with Erdogan.

"We have been told different things as to why he did not accept the invitation," Erdogan said. "But none of them had anything to do with the Patriots."

Iran has detailed a six-point plan to put an end to the crisis in Syria, calling for an immediate ceasefire and the start of national dialogue between Damascus and rebel forces.

However, opposition groups reject any Iranian involvement in the search for a solution, reflecting the view that the US and some Western and Arab countries hold that Tehran is discredited by its unwavering support for Assad.

And Turkey, which pioneered a regional mechanism involving Tehran and Egypt to end the Syrian conflict, backs Tehran's plan as long as it leads to a solution, a Turkish foreign ministry official said.

"Turkey backs every initiative which will help stop the bloodshed in Syria and welcomes every effort in this regard," the diplomat told AFP, when asked about the Iranian plan.