Turkey, an important trade partner for Syria, has grown frustrated with Assad over his crackdown on protests [EPA]

Turkey has imposed an arms embargo on Syria for its crackdown on the country's uprising, saying that it has already stopped a Syrian-flagged ship.

Officials have not said where or when the vessel was stopped and whether any weapons were found aboard it.

"If there are planes carrying weapons, or such shipments by land, then we would stop and confiscate them as in the past," the state-run Anatolia news agency quoted Recep Tayyip Erdogan, the prime minister, as saying on Friday.

Turkey intercepted an arms shipment from Iran to Syria in August. In March, Turkish authorities also seized the cargo of an Iranian aircraft bound for Syria because the shipment violated UN sanctions.

Turkish media said the aircraft was carrying light weapons, including automatic rifles, rocket launchers and mortars.

Co-ordinated efforts

Erdogan said this week that Turkey was co-ordinating its efforts with the US.

The US has called on Bashar al-Assad, the Syrian president, to resign and imposed sanctions on some Syrian officials, blocked assets they may have in the US and banned any US import of Syrian oil or petroleum products.

Erdogan said after talks with US President Barack Obama in New York late Tuesday that he was no longer in contact with Syria's leadership.

“I have cut all contacts with the Syrian administration,'' Erdogan said.

“We never wanted things to arrive at this point, but unfortunately, the Syrian administration has forced us to take such a decision.''

Turkey is Syria's neighbour and an important trade partner and Erdogan had cultivated a close friendship with Assad.

However, Turkish leaders have grown increasingly frustrated with Syria over its refusal to halt the crackdown on opposition protesters and to carry out reforms.

Earlier this month, Turkey hosted a group of Syrian opposition figures who declared a 140-member Syrian National Council in an effort to present a united front against Assad.

At least 7,500 Syrians are seeking refuge from the violence in six camps near the border in Turkey.