
U.N. observers investigated the latest reported massacre in Syria, entering a village Saturday where activists say regime forces killed dozens of people the past week, as Turkey's prime minister blasted Damascus' leadership, warning that the Syrian people will "make them pay" for such mass killings.

In a show of force, Syria began large-scale military exercises Sunday to simulate defending the country against outside "aggression." Damascus' staunch ally Iran warned of a "catastrophe" in the region if no political solution to the 16-month-old Syrian conflict is found.

Angry crowds blocked United Nations observers from reaching an embattled rebel-held town in Syria on Tuesday, hurling stones and metal rods at the monitors' vehicles. Their vehicles came under fire as they drove away from Haffa, but the source of the gunfire was not clear, the U.N. said.

International envoy Kofi Annan said Monday he was "gravely concerned" about the escalation of fighting in Syria, citing the shelling of opposition areas in central Homs province and reports of mortar, helicopter and tank attacks near the Mediterranean coast.

A team of international observers was evacuated Wednesday from a tense town in northern Syria a day after their convoy was hit by a roadside bomb, a U.N. spokesman said.

U.N. Secretary-General Ban Ki-moon said Monday the Syrian government is responsible for guaranteeing U.N. observers full freedom of movement to monitor the country's tenuous cease-fire, which appeared to be unraveling as regime forces pounded the opposition stronghold of Homs, activists said.

U.N. Secretary-General Ban Ki-moon said Monday that the Syrian government is responsible for guaranteeing U.N. observers full freedom of movement to monitor the country's tenuous cease-fire, which activists say appeared to be unraveling as regime forces pounded the opposition stronghold of Homs.

Syria's 4-day-old cease-fire appeared to be eroding quickly on Sunday, with regime forces firing dozens of tank shells and mortar rounds at neighborhoods in the opposition stronghold of Homs, hours before the arrival of a first team of U.N. truce monitors.

For the first time since the Syrian conflict began more than a year ago, the U.N. Security Council on Saturday united behind a legally binding resolution calling for violence to end immediately and peace talks to begin.