STOCKHOLM/ANKARA — Turkey is not providing shelter or backing to al-Qaida-linked groups in Syria and will continue to exclude them from its broader support for the Syrian opposition, Turkish Prime Minister Tayyip Erdogan said on Thursday.

Turkey has long championed more robust backing for Syria's fractious armed opposition, but the rise of al-Qaida-linked groups among their ranks has left it open to accusations that it is lending support to radical Islamists.

"It is out of the question that groups like al-Nusra and al-Qaida can take shelter in our country," Erdogan told a news conference in Stockholm during an official visit.

"On the contrary, any such structures would be subject to the same fight we carry out against separatist terrorist groups. We have taken the necessary steps against them and we will continue to do so," he said.

Al-Qaida-linked groups such as Jabhat al-Nusra and the Islamic State of Iraq and the Levant (ISIL) have captured territory in parts of northern Syria near the border in recent months, raising alarm among the opposition's Western backers.

Turkey has maintained an open-door policy throughout the nearly three-year conflict, providing a lifeline to rebel-held areas by allowing humanitarian aid in, giving refugees a route out and letting the rebel Free Syrian Army organize on its soil.

"Who we recognize among the Syrian rebels is a known fact. We are in contact with the Free Syrian Army . . . and we are also in touch with the [opposition] Syrian National Coalition," Erdogan told the news conference. "We provide all of our support and aid through these."

GENEVA TALKS

Erdogan said 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 United States and Russia failed at a meeting chaired by U.N.-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 pre-conditions," 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 (560-mile) 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.