The comments by Syria's powerful neighbor indicated the latest violence had put Assad beyond redemption in Ankara's eyes, despite his once-close friendship with Turkey.

"The Syrian regime is committing a crime against humanity every day," Davutoglu told a joint news conference with visiting Italian Foreign Minister Giulio Terzi.

"I am saying this clearly, after these many massacres and crimes, which have characteristics of war crimes, the Syrian regime closes all doors to dialogue."

Ankara has been at the forefront of efforts to nurture the Syrian opposition since abandoning Assad, hosting the Syrian National Council and sheltering members of the Free Syrian Army.

A report on the state-run Anatolian news agency website said Syrian troops backed by tanks had seized the village of Ain al-Beida, near the border with Turkey, in a pre-dawn assault on Saturday. Some wounded people had fled across the frontier for treatment, the agency said.

Hours earlier at a meeting in Istanbul, SNC representatives pressed Davutoglu to provide immediate humanitarian assistance to people trapped by Assad's forces inside Syria.

Turkey will host a meeting of the international community, mainly Arab countries and Western powers, in Istanbul later this month as a follow-up to the "Friends of Syria" meeting in Tunis in February.

"ORGANISED MASSACRE"

Secretary-General Ban Ki-moon piled pressure on Assad's government at the General Assembly on Friday, referring to "grisly reports" of arbitrary execution, imprisonment and torture, as well as heavy civilian losses during the assault on the Baba Amro district of Homs, Syria's third largest city.

Davutoglu and Terzi also condemned Syria for denying an international aid convoy access to Baba Amro.

"As savagery of this magnitude goes on, the blocking of humanitarian aid or not admitting UN representatives to Syria is also a separate crime," Davutoglu said.

"The recent incidents in Baba Amro and those that took place in Zabadi before that, and previous incidents in other cities, have become an organized massacre campaign run by a regular army against its own people.

U.N. officials estimate that more than 7,500 people have been killed in Syria during almost year-long crackdown.

"They used to intervene using bullets against protesters. Now they are bombarding the cities with people inside. This is unacceptable, even under conditions of war," said Davutoglu.

The Syrian government said in December that "armed terrorists" had killed more than 2,000 soldiers and police during the unrest.

EXILE OPTION

Terzi said Assad had lost legitimacy as a leader and should seek terms to go into exile as Yemeni President Ali Abdullah Saleh had done, allowing the election of a new leader.

"There must be a change," he said. "The Yemen solution is the most practicable."

Davutoglu's suggestion that Assad could be guilty of war crimes indicates how Ankara has lost patience with their one-time ally. A year ago, Ankara criticized Western powers for accusing Muammar Gaddafi of crimes against humanity, arguing it would box him in and leave the Libyan leader with no option but to fight to the death.

The Turkish minister went onto compare slaughter in Syria to the carnage during the Bosnian civil war in the 1990s, and took a swipe at the United Nation's Security Council for not taking a stronger stand due to vetoes from Russia and China.

"The current picture resembles Sarajevo and Srebrenica more and more every day. Unfortunately, the lack of consensus of the international community encourages the regime," he said.

*Writing by Simon Cameron-Moore; Editing by Ben Harding