Opposition activists say Syrian warplanes struck a strategic, rebel-held town on the Damascus-Aleppo highway Tuesday, killing at least six civilians, including three young girls, following a widely ignored four-day truce between government forces and insurgents.

The air raids and fighting in Maarat al-Numan continued as ground troops attempted to recapture the Sunni Muslim area recently taken by rebels. Their presence has disrupted the government's ability to send supplies and reinforcements to Aleppo, where the two sides are bogged down in a bloody fight for control of the country's largest city.

Tuesday's airstrikes came a day after the Britain-based Syrian Observatory for Human Rights reported the fiercest air raid campaign in Damascus since the uprising began 19 months ago, targeting a number of rebel-held suburbs.

Also on Tuesday, Syrian state television reported that an air force general was killed in a Damascus suburb, the latest in attacks against senior members of President Bashar al-Assad's administration.

The report blamed “terrorists” for what it called the assassination of General Abdullah Mahmoud Al-Khalidi.

Meanwhile, activists also said the Syrian army and rebels are clashing in a Palestinian refugee camp in the capital.

Palestinians have largely stayed out of the war in Syria. The country is home to nearly 500,000 U.N.-registered Palestinian refugees.

The fighting in Syria has continued uninterrupted despite a truce called for the Muslim Eid al-Adha holiday, which quickly broke down before ending Monday.