Syria’s ceasefire came under significant threat Sunday as the government of President Bashar Assad vowed a crackdown on a wave of “terrorist attacks” and its forces shelled Homs on the day the first UN peace monitors were due to enter the country.An initial team of UN ceasefire monitors was due to arrive late Sunday evening and will be deployed on Monday in an effort to keep the peace plan on track, the spokesman for international mediator Kofi Annan said.Syria said it would stop what it called “terrorist groups” from continuing criminal acts, state TV quoted a security source as saying, casting further doubt on whether the cease-fire would hold.“[Security forces], based on their duty to protect civilians and the country, will stop terrorist groups from continuing their criminals acts and the killing of civilians,” the state news agency SANA said. “Since the announcement of an end to military operations, terrorist attacks have increased by dozens, causing a large loss of life.”The Arab League – which along with the United Nations backed negotiations by Annan leading to the declaration of a cease-fire – welcomed the Security Council decision to send in monitors.“The Arab League welcomes this decision as it represents an international will to support the mission of the joint envoy Kofi Annan,” Egypt’s news agency MENA said, quoting Deputy Arab League Chief Ahmed Ben-Helli.Ben-Helli said Annan would report on his mission at an Arab League meeting on Syria on Tuesday in Qatar.“Early this morning, we saw a helicopter and a spotter plane fly overhead.Ten minutes later, there was heavy shelling,” said an activist living in the battered Homs district of Khalidiya.Activist video footage, reportedly from Khalidiya, shows an explosion shortly after the sound of a missile flying through the air. Another whiz follows, and the cameraman, standing in a nearby building, pans across to show a ball of flames and smoke rising into the air.Rami Abdelrahman, head of the British-based Syrian Observatory for Human Rights, said shells were being fired at a rate of one per minute. He said there had also been overnight clashes in rural Aleppo.“People said they heard explosions and shooting after rebels attacked a police station and then clashed with police,” he said.Although violence has continued throughout the cease-fire, there has been a significant drop in the daily death toll in fighting which has often killed more than 100 people a day.Still, Abu Rabea, an activist in Homs, dismissed the cease-fire and the monitoring mission.“Nothing has changed in Homs, government loyalists on roofs are using heavy machine guns to shoot us and we are being shelled. The only thing that has changed is that Kofi Annan’s plan is said to be accepted by the regime and the world believes them.”The Security Council resolution condemned the “widespread violations of human rights by the Syrian authorities, as well as any human rights abuses by armed groups.”The text, supported by Russian and China – which had vetoed previous Syria resolutions – included a vague warning to Damascus, saying the council would “assess the implementation of this resolution and to consider further steps as appropriate.”US Ambassador to the UN Susan Rice condemned what she said was Syria’s “murderous rampage” over the last year. Asked if Syrian government shelling of Homs on Saturday was a violation of the cease-fire, Rice said: “Absolutely.”The UN estimates Assad’s forces have killed more than 9,000 people in the uprising.They will be joined by two dozen more observers in the coming days in line with a UN Security Council resolution adopted on Saturday authorizing the deployment of up to 30, the spokesman said.But four days after the cease-fire brokered by Annan was meant to come into effect, regime-sponsored violence persisted, particularly in the battered city of Homs.Analysts remain skeptical that monitors will alter the dynamics of the Syria crisis.In December, the Arab League dispatched more than 60 monitors to the country, only to withdraw them a month later due to what it described as safety concerns.“If they’re even let into blighted areas, they’ll be told certain parts are inaccessible due to ‘security concerns,’” Michael Weiss of the London-based Henry Jackson Society told The Jerusalem Post. “Also, 30 people to cover a country is farcical – even if this is just an advance team.”“The cease-fire hasn’t held,” he said. “The regime has renewed its use of attack helicopters and artillery in Homs. Peaceful protests in Aleppo and elsewhere have been violently dispersed. So any attempt to try and see it implemented further is both hypocritical and time-wasting.”Michael Rubin of the American Enterprise Institute said he believes Annan was the wrong choice for international envoy to Syria.“No dictator worth his salt is afraid of Kofi Annan and his UN monitors.After all, as head of peace-keeping, Annan had presided over the Rwanda genocide and then as secretary-general, Annan had called Saddam Hussein ‘a man I can do business with.’” All the cease-fire will do is remove some of the heat off Assad, Rubin says, “as his forces regroup and unload the generous arms packages the Russians and Iranians provide, and then the process will start all over again.”On Sunday, the Syrian government said it could not be responsible for the safety of the monitors unless it is involved in “all steps on the ground,” government spokeswoman and presidential adviser Bouthaina Shaaban said.She also said the number of monitors could rise to 250, but that Syria reserved the right to agree on the nationality of those participating.On the day the first observers were due in Syria, government forces bombed the city of Homs, one of the hotbeds of opposition to Assad, at a rate of “one shell per minute,” activists said. They also reported attacks elsewhere in the country.