BEIRUT — Airstrikes in a Damascus suburb have killed eight people, including children, the area’s first casualties since Russia said three days ago that it reached an agreement with the Syrian opposition on the boundaries for a deescalation zone in the capital’s eastern suburbs, opposition activists and a paramedic group said on Tuesday.

The airstrikes on Arbeen, just before midnight Monday, also caused material damage. Damascus residents said insurgent groups fired several shells an hour later that fell near the Russian embassy in Damascus with no reports of casualties.

The Syrian Civil Defense group, more popularly known as the White Helmets, and the Britain-based Syrian Observatory for Human Rights say the airstrikes on Arbeen killed eight and wounded dozens. The White Helmets said the eight killed included five children and two women.

In neighboring Lebanon, two international human rights groups called on Lebanese authorities to disclose their findings into the fate of four Syrian refugees who died while in custody of the Lebanese army.

The four were detained in a sweeping security raid late last month in refugee settlements in and around the border town of Arsal that netted 355 Syrians. The town was the scene of a major cross-border attack in 2014, when more than two dozen Lebanese soldiers were abducted.

A Lebanese military probe aired on state-run media on Monday said the four died of natural causes.