Abdel Kamble, a spokesman for SANA, the Syrian state news media office, confirmed that two people were killed.

“SAA soldiers and terrorists fired at each other several times along and close to the city’s front lines,” another SANA official told Reuters by telephone, referring to the forces of Mr. Assad and some of his opponents.

Reuters reporters who travelled to Harasta, which is close to the border with Lebanon, to cover the crisis witnessed multiple shells landing in residential areas. The Lebanese security forces responded by firing their mortars and rockets to the rebel-held area.

According to the Syrian Observatory for Human Rights, the death toll included at least 13 SAA soldiers who were killed in shelling.

Mr. Assad, who seized power in a coup in 1970 but later went into exile in Jordan, has been battling for power with local opposition forces, which have formed mostly Sunni-dominated militias. In November, at least 27 people were killed in a day of violence in Damascus.

Syrian jets have hit rebel targets in Harasta in recent days and, earlier this month, bombed a rebel supply line. But Mr. Kamble said there were no clashes Wednesday against the opposition.

Mr. Kamble said no rebel fighters went into Harasta from the nearby town of Maarat al-Numan, where a major protest was set up in the spring, but that rebels also fought in Harasta on Saturday.

An opposition delegate who spoke on condition of anonymity because he was not authorized to brief reporters said that Mr. Assad’s forces were attacking the city to “smash anyone who tries to take it back.”