At least 67 people were killed in Syria on Tuesday as regime forces bombed several towns in Syria despite the arrival of U.N. observers responsible for assessing compliance with the cease-fire.
The head of an advance team of six unarmed United Nations observers, Moroccan colonel Ahmed Himmiche said, "We are facing a difficult job firming up the cease-fire.
"No cease-fire, not even the beginnings of a political process -- this mission will be one of the toughest ever undertaken by the United Nations," Himmiche told reporters.
The advance team of the observers arrived late on Sunday in Syria, after the U.N. Security Council approved a resolution aimed at putting an end to the violence that engulfed Syria for over a year.
However, the cease-fire seems increasingly fragile, raising doubts among Western countries over the implementation of the peace plan by President Bashar al-Assad's regime.
Under Annan's plan, Damascus was to withdraw its troops and heavy weapons from restive areas across Syria after a cease-fire and start a dialogue with the opposition.
In Moscow, Russian Foreign Minister Sergei Lavrov warned against any attempt from "outside forces" to torpedo the efforts of the U.N. Security Council regarding the Syrian crisis. "Some states and forces outside the country do not want the success of the current efforts by the U.N. Security Council," he said in Moscow after meeting with his Abkhaz counterpart.
"I hope all those will act in the interests of the Syrian people, and not according to their political ambitions," Lavrov said at a news conference.
However, the Russian minister declined to specify the names of these countries.
He said these forces "are trying to replace the Security Council by non-official training of the "Friends of Syria "(...) and encourage the Syrian opposition not to cooperate with the government to establish a dialogue or a truce."
Meanwhile, the U.S. Secretary of State Hilary Clinton says that the U.S is working on a new package of measures to be taken against Damascus should it sabotage the U.N. and Arab League mission.