BEIRUT – The head of the U.N. observers’ mission in Syria demanded Sunday that warring parties allow the evacuation of women, children, elderly and sick people endangered by fighting in the besieged city of Homs and other combat zones.

Maj. Gen. Robert Mood said the observers had been trying for the past week to bring out families and wounded trapped in the central city of Homs by heavy shelling of rebel-held areas. The offensive is part of a broader push by President Bashar Assad’s forces to regain rebel-held villages and towns throughout the country.

“The parties must reconsider their position and allow women, children, the elderly and the injured to leave conflict zones without any preconditions and ensure their safety,” Mood said in a statement. U.N. “attempts to extract civilians from the line of fire over the past week have been unsuccessful.”

“This requires willingness on both sides to respect and protect the human life of the Syrian people,” he said.

On Saturday, the U.N. said its 300 observers based in Syria were suspending all missions because of concerns for their safety after fighting intensified over the previous 10 days. But the monitors said they were remaining in Damascus.

A U.N. official said earlier Sunday that a team of observers had left Damascus for Homs, hoping to evacuate civilians. The plan was not made public for fear that would compromise the mission.

The official said the plan was to arrange a brief cease-fire of up to 90 minutes during which the civilians would have been evacuated from rebel-held areas of Homs through a safe corridor. He said the mission was approved by the Syrian government. But the fighting never eased enough to allow the evacuations.

Regime forces have been waging a fierce offensive through towns and villages nationwide, trying to root out rebels by shelling urban areas with tanks and attacking from helicopters. Rebels also have attacked Syrian forces, mostly trying to burn tanks.

The activist group Syrian Observatory for Human Rights said at least eight soldiers were shot and killed in one rebel attack, and some 30 Syrian civilians and rebels were killed across the country Sunday.

“The humanitarian situation in Homs is very difficult,” said Rami Abdul-Rahman, who heads the British-based Observatory. “It is very clear that the army wants to retake Homs.”

The Observatory asked the U.N. on Saturday to intervene in Homs to evacuate 1,000 families the group said were trapped along with dozens of wounded people in rebel-controlled areas who could not get medicine or doctors to treat them.

On Sunday, clashes appeared particularly intense in Homs and its surrounding provinces as well as in the town of Douma on the fringes of the Syrian capital, said the Observatory and the Local Coordination Committees, another activist group. Amateur video showed plumes of smoke wafting over Homs as gunfire echoed and shells slammed into concrete and metal.