BEIRUT (Reuters) - Heavy shelling by Islamic State militants killed at least seven people in the eastern Syrian city of Deir al-Zor on Sunday night, a war monitoring group said.

The Syrian Observatory for Human Rights, a Britain-based organization that monitors the war, said the militants continued to shell the city’s government-held districts on Monday.

Islamic State holds most of Deir al-Zor province, apart from an enclave in the city and a nearby air base that Syrian government forces control.

The militants have besieged those districts for nearly two years. The Syrian government and its Russian ally have made regular aid drops into the encircled zone, where about 200,000 people live, lacking food and medicine.

Deir al-Zor province links territory Islamic State controls in Syria and Iraq.