Russian President Dmitry Medvedev on Friday cautioned against attempts to circumvent the authority of the United Nations as the West seeks to secure Moscow's support in the Syria crisis.

"There's a need to eliminate any loopholes allowing (nations) to act in circumvention of the authority of the Security Council and use force without its approval," Medvedev told a European security conference in Moscow.

Fierce clashes erupted in Syria on Thursday, with a busload of fleeing civilians among 110 killed, as President Bashar al-Assad's foes described a U.N. Security Council peace call as toothless.

The army attacked a string of towns, while rebel fighters struck military posts in several provinces and announced a command structure to coordinate hit-and-run strikes in and around Damascus.

An international action plan is needed to stop the "human tragedy" in Syria, Turkey's foreign minister said Thursday after a U.N. Security Council statement calling for all sides to end violence.

"In addition to a common message we also have to develop a joint plan of action," Ahmet Davutoglu said after talks in Vienna with his Austrian counterpart ahead of an EU foreign ministers' meeting in Brussels that he will attend.

At least 30 people were killed in Syria on Tuesday as the U.N. Security Council discussed the violence and long-time Damascus ally Russia said President Bashar al-Assad had "made a lot of mistakes."

Moscow's comments came as U.N.-Arab League envoy Kofi Annan and Arab League chief Nabil al-Arabi called for a united international stand on the crisis.

Russia said Tuesday it was willing to support either a U.N. Security Council statement or a resolution on peace envoy Kofi Annan's mission to Syria as long as it contained no ultimatums.

"We are ready to back the mission of U.N. and Arab League representative Kofi Annan and the proposals to the government and opposition to Syria," Foreign Minister Sergei Lavrov told reporters after holding talks with his Lebanese counterpart Adnan Mansour.

Head of the Special Tribunal for Lebanon’s defense office Francois Roux arrived in Beirut overnight Monday and swiftly held closed-door meetings with officials.

Al-Joumhouria newspaper reported Tuesday that Roux will seek to “urge the Lebanese to take part in the tribunal’s work to guarantee the rights of the victims of the attacks, the accused and those who were harmed.”

U.N. secretary-general Ban Ki-moon said Tuesday that the situation in Syria has become unacceptable and called on the Security Council to unite on the issue.

"The situation in Syria has become an unacceptable and intolerable situation," Ban said in Bogor, Indonesia, where he addressed the country's peacekeepers working for the U.N.

President of the Special Tribunal for Lebanon Judge Sir David Baragwanath will arrive in Lebanon on April 1, al-Akhbar newspaper reported on Monday.

“Baragwanath has informed the Lebanese authorities about his expected visit in an official letter sent to Lebanon’s embassy” in the Netherlands, sources told the daily.

Thousands of protesters gathered outside the White House Saturday to demand that the United States "stop the massacre in Syria," where an estimated 8,000 people have been killed in a regime crackdown.

Wearing T-shirts declaring "I have a dream of a free Syria" and "No longer afraid," the demonstrators -- who numbered 4,000, according to organizers -- were marking the first anniversary of a bloody revolt against President Bashar Assad's regime.

United Nations Interim Forces in Lebanon Commander General Paolo Serra said on Saturday that the peacekeeping mission is determined to halt the hostile practices between Lebanon and Israel and implement the U.N. Security Council resolution 1701.

“The past five years were the calmest period in southern Lebanon’s history… and the UNIFIL is determined to help the two parties to maintain a stable cease of hostile practices,” Serra said during a medal ceremony at the Irish contingent headquarters.