International envoy Kofi Annan has expressed “alarm” about media reports that Syrian troops have attacked civilian areas visited by U.N. soldiers trying to monitor a shaky truce in the government's year-long conflict with rebels.

U.N. diplomats say Mr. Annan made the comment Tuesday in a closed-door briefing to the U.N. Security Council via video link from Sweden. They quote Mr. Annan as saying he is aware of reports that Syrian troops fired automatic weapons and killed a significant number of people in the central city of Hama on Monday. Several U.N. observers had visited the opposition hub a day earlier and were greeted by large crowds chanting anti-government slogans.

Mr. Annan said if confirmed, the Hama killings are “totally unacceptable and reprehensible.” He said two of the 11 U.N. monitors deployed in Syria returned to the city on Tuesday to set up a base. Observer mission spokesman Neeraj Singh said the monitors also visited the Damascus suburb of Douma, talking to residents and conducting patrols “for a good period of time.”

U.S. Secretary of State Hillary Clinton said Tuesday that harassment and possible violence against Syrians who meet with U.N. monitors is “absolutely deplorable.”

The small group of U.N. truce monitors has been operating in Syria for more than a week, visiting rebellious areas such as Hama, Homs and the Damascus suburbs, where government forces have been violently suppressing dissent for months. The U.N. Security Council approved an expansion of the observer mission to 300 personnel last week.

Diplomats quote Mr. Annan as saying that a speedy deployment of the additional monitors is “crucial” to verify compliance by Syrian government and rebel forces with the April 12 cease-fire. But U.N. peacekeeping chief Herve Ladsous told the Security Council it will take a month for the first 100 members of the mission to be in place. Exiled Syrian opposition leaders say that number is too small to cover Syria's territory.

Mr. Annan also told the council that he received a letter from Syrian Foreign Minister Walid al-Moualem saying Damascus has withdrawn troops and heavy weapons from population centers as required by the U.N.-backed truce.

Earlier, Mr. Annan's spokesman said Syria has failed to honor that commitment. Ahmad Fawzi said Tuesday Mr. Annan's team has satellite imagery and credible reports showing the Syrian government's promised pullout “has not fully happened.” Fawzi called this “unacceptable.”

In the latest violence Tuesday, the British-based Syrian Observatory for Human Rights told VOA that gunmen killed a Syrian intelligence officer in the Barzeh neighborhood of Damascus. In another incident, a vehicle rigged with explosives blew up in the capital's central Marjeh district, wounding several people. Syrian state media blamed the attack on “armed terrorists” whom they say are leading the anti-Assad uprising.

In Geneva, the U.N. World Food Program said it aims to deliver food assistance to 500,000 people in Syria “in the coming weeks” — a tenfold increase since December. The WFP said it is expanding its assistance at the request of the Syrian Arab Red Crescent and stands ready to increase its operations in the country further “when access permits.”

U.N. aid agencies have been largely shut out of Syria, but a joint assessment carried out last month with Syrian authorities estimated that at least 1 million people needed humanitarian aid.

Meanwhile, Tunisian President Moncef al-Marzouki said his embattled Syrian counterpart is “finished” and will eventually leave power “dead or alive.” Mr. Marzouki told the pan-Arab Al-Hayat newspaper Tuesday that Mr. Assad's international allies, “the Russians, Chinese and Iranians, must understand this man is finished and…persuade him to leave power.”

Addressing the Syrian leader directly, the Tunisian president said “it is better for you and your family to leave alive, because if you decide to leave dead, that means that you have caused the deaths of tens of thousands of innocents.”

The United Nations estimates that more than 9,000 people have been killed in Syria's 13-month crackdown on the revolt, while activist groups put the death toll at more than 11,000.