BEIRUT: A Syrian airstrike has killed a senior commander of the Liwa Al-Tawhid rebel brigade in Aleppo and wounded its chief and another leader, a watchdog said Friday.

Four other rebel chiefs were killed in separate incidents, two in the northern Aleppo province and the others in the south of the country, the Syrian Observatory for Human Rights said.

Yussef Al-Abbas, known as Abu Al-Tayyeb, was intelligence chief for Liwa Al-Tawhid and was killed in a strike Thursday on an army base captured by the rebels a year ago, the Britain-based Observatory said.

He had been in a car along with the brigade’s top commander, Abdelkader Saleh, and another senior figure of the group, Abdelaziz Salameh, both of whom were wounded. Following the attack, Liwa Al-Tawhid arrested 30 people suspected of being informers for the regime of President Bashar Assad.

The powerful brigade is among a number of units that have rejected the mainstream opposition Syrian National Coalition.

In separate incidents, two chiefs of rebel battalions were killed in fighting with loyalist forces near the international airport outside Aleppo.

A former army colonel who commanded another rebel brigade was killed in fighting in the Maarat Al-Artiq area.