The United States said Monday that the U.N. Security Council has been a "colossal failure" in protecting Syrian civilians and made a new demand for sanctions against President Bashar Assad.

The council, which is divided on how to end the conflict, "continues to stand by, rather than to stand up," Susan Rice, U.S. envoy to the United Nations, told the 15-nation body.

A Russian ship that tried to deliver repaired attack helicopters to Syria raised Russia's tricolor flag on Monday as it awaited orders in a naval port to possibly make a second attempt, a report said.

The Alaed cargo vessel dropped anchor at the main base of Russia's Northern Fleet near the city of Murmansk on Sunday after being forced to turn back when its British insurer dropped coverage on learning of the mission's true intent.

A rescue plane searching for a Turkish fighter jet that had been shot down over the eastern Mediterranean was itself placed in the crosshairs by the Syrian military, a European diplomat told Agence France Presse on Monday.

The Turkish army Casa CN-235, a twin-propeller transport, was targeted by a Syrian ground-to-air defense system as it looked Friday for the F4 Phantom jet that had been downed earlier with its crew of two, said the diplomat.

The 57-member Organization of Islamic Cooperation's executive committee has recommended suspending Syria's membership in the pan-Muslim grouping, it said in a statement on Monday.

The committee has "recommended to the meeting of the council of foreign ministers to be held in Djibouti the suspension of Syria's membership in the OIC in light of the bloody events taking place in the country," said the statement that followed a meeting in Saudi Arabia late Sunday.

Syrian Foreign Ministry spokesman Jihad al-Makdissi on Monday insisted that a Turkish F-4 Phantom jet its forces shot down on Friday had "violated Syrian sovereignty."

"The Turkish warplane violated Syrian airspace, and in turn Syrian air defenses fired back and the plane crashed inside Syrian territorial waters," he told a news conference that he said would "refute the lies" of Turkish officials.

The European Union imposed fresh sanctions on President Bashar Assad's regime Monday, targeting six government ministries and firms and one individual, while clarifying an existing EU arms embargo.

The measures were approved by foreign ministers of the 27-nation-bloc meeting in Luxembourg, an EU statement said.

Russian President Vladimir Putin arrived in Israel on Monday for talks with Israeli and Palestinian leaders against the backdrop of sustained violence in Syria and concern on Iran's nuclear program.

Putin arrived around midday (09:00 GMT) for a first stop in the northern Israeli town of Netanya, where he was to participate in the unveiling of a memorial honoring the role of the Red Army in World War II.

Another general and some 30 soldiers have fled to Turkey from neighboring Syria and joined the swelling ranks of rebel soldiers based close to the border, the Anatolia news agency reported on Monday.

The defection brought to 13 the number of generals seeking refuge in Turkey since the revolt against Syrian President Bashar Assad's regime erupted 16 months ago.

France's Foreign Minister Laurent Fabius welcomed Monday's agreement to impose fresh EU sanctions against Syria but called on the 27-nation bloc "to go further".

"I'm satisfied that these new sanctions have been adopted but I would like to go further," Fabius told a news conference held during talks between European Union foreign ministers.

Syrian troops pounded the central city of Homs on Monday, activists and monitors said, amid warnings from the rebel Free Syrian Army (FSA) of an impending "massacre" there.

Main opposition bloc the Syrian National Council (SNC) issued a distress plea from residents, urging international help "before it is too late."