DAMASCUS, Syria — The secretary general of the Syrian Arab Red Crescent and a Christian priest have been killed in violence that flared in parts of Syria on Wednesday, as Arab and Western nations continued their attempts to isolate Syria by trying to unseat it from two committees at a United Nations agency.

The Red Crescent official, Dr. Abd-al-Razzaq Jbeiro, was shot and killed while traveling on the Halab-Damascus highway in a vehicle that was “clearly marked with the Red Crescent emblem,” according to a statement released by the International Committee of the Red Cross.

The priest, from the Greek Orthodox Church, the Rev. Basilious Nasser, was shot and killed on the second day of heavy fighting in the city of Hama. The Syrian state news agency blamed an “armed terrorist group” for the killing, while opposition activists in Hama said the priest was shot by a government sniper.

Demonstrations and clashes were also reported on the outskirts of Damascus as the country braced for more violence, after a promise by Syria’s foreign minister on Tuesday that the government would deal “firmly” with armed groups that had recently stepped up their confrontations with security forces.