Russia on Tuesday warned both sides in Syria against disrupting the work of U.N. observers in the conflict-torn nation and called their work crucial to providing an unbiased picture on the ground.

"The more observers there are, the more information we get that is based on objective facts and that is free from speculation," Russian Foreign Minister Sergei Lavrov said while on a visit to the Central Asian state of Tajikistan.

A car bomb exploded in central Damascus on Tuesday, wounding three people, state television reported, blaming an "armed terrorist group".

"An armed terrorist group detonated the car bomb near the Yelbugha complex in the Marjeh district of Damascus, wounding three people and causing damage to nearby buildings," the television said.

Nearly 60 people were reported killed in violence across Syria on Monday despite a hard-won ceasefire and the upcoming deployment of 300 U.N. observers to monitor the truce, a watchdog said.

The Syrian Observatory for Human Rights said on Tuesday a total 54 civilians and five soldiers were killed in various provinces.

Syria's embattled President Bashar al-Assad is "finished" and will eventually leave power "dead or alive," his Tunisian counterpart Moncef Marzouki said in a newspaper interview published on Tuesday.

"The Russians, Chinese and Iranians," who have been supporting Assad since an uprising against his rule erupted last year, "must understand that this man (Assad) is finished and that it is no longer possible to defend him," Marzouki told the pan-Arab Al-Hayat daily.

A Fatah al-Islam Lebanese militant, who was accused of targeting the Lebanese army, was killed in the Syrian city of Qsair after detonating himself accidentally, the Time reported.

According to a fellow fighter, who goes by the nom de guerre of Abu Ali, Abdul Ghani Jawhar had been preparing an explosive device to be used against the Syrian army when it went off prematurely, killing him instantly.

U.S. President Barack Obama Monday ordered new sanctions on Syria and Iran and the "digital guns for hire" who help them oppress their people with surveillance software and monitoring technology.

Obama announced additions to the pile of U.S. sanctions already faced by the two governments as part of a wider effort to crack down on human rights abuses, atrocities and genocide, at a speech at the U.S. Holocaust Museum.

Syrian troops killed 44 people across the country on Monday, including 34 civilians in the central city of Hama alone, monitors said, as U.N. military observers toured protest centers near the capital and both the European Union and the United States imposed new sanctions.

Regime forces killed 35 people in Hama, three in the southern province of Daraa, two in the central province of Homs, one in the northwestern province of Idlib and one in the eastern protest hub of Deir Ezzor, the Local Coordination Committees, the main activist group spurring protests on the ground, said.

The army intelligence foiled an attempt by three men to smuggle weapons to Syria, the National News Agency reported on Monday.

Two Lebanese men and a Syrian national were detained after the army confiscated their pick-up truck in Beirut.

United Nations ceasefire monitors were touring towns near the Syrian capital on Monday, an official said, as the European Union slapped new sanctions on the regime of Bashar Assad.

Neeraj Singh, spokesman for an eight-member advance team of U.N. observers deployed in Syria, said monitors would be visiting areas near Damascus in hopes of making sure a tenuous ceasefire that went into effect April 12 sticks.

The European Union agreed Monday to slap new sanctions on the Syrian regime, banning luxury goods exports and further restricting the sale of items used to repress dissidents, a diplomat said.

"These sanctions will be put in place against Syria," the diplomat told AFP after EU ambassadors endorsed the measures ahead of a meeting of foreign ministers in Luxembourg.