Turkish Prime Minister Tayyip Erdogan said Thursday that Turkey supported a planned internationally backed peace conference on Syria but blamed Russia, one of Syrian President Bashar Assad's key allies, for the failure this week to agree on a date for the talks.
The U.S. and Russia failed at a meeting chaired by United Nations-Arab League envoy Lakhdar Brahimi on Tuesday to agree a date for the so-called Geneva 2 conference.
"The process was again postponed. Why? Because Moscow is telling the opposition to accept a transitional government with Assad's involvement," Erdogan said.
"Come and sit at the table, and leave behind all the preconditions," he said.
Turkey has become one of Assad's fiercest critics and has insisted he cannot be part of any transitional government, but it denies arming the rebels or facilitating the passage of foreign fighters who have swollen the ranks of factions including ISIL and Nusra.
Its 900-kilometer border is, however, difficult to police, and refugees, smugglers and rebel fighters have been able to cross undetected in remote areas, bypassing main checkpoints.
The governor of Turkey's southern province of Adana, Huseyin Avni Cos, was quoted by Turkish media on Thursday as saying a truck loaded with 1,200 rocket warheads, bazookas, explosives and guns was seized near the border and nine people detained.
Initial investigations suggested the warheads had been produced in Turkey, Cos told state broadcaster TRT. It was not clear who the weapons were destined for.