The Latest: Activists say IS evacuating Raqqa over dam fears

BEIRUT (AP) - The Latest on the Syrian conflict (all times local):

2:45 p.m.

Syrian activists say the Islamic State group has ordered an evacuation from its de facto capital, Raqqa, following warnings that the Tabqa Dam upstream on the Euphrates River could collapse.

The activist-run Raqqa is Being Slaughtered Silently says civilians are fleeing Raqqa en masse. It says the militants are warning residents that the dam is out of service, weakened by U.S.-led coalition airstrikes, and could collapse. It says water levels are rising behind the dam.

The Britain-based Syrian Observatory for Human Rights, an opposition-run monitoring group, is also reporting the dam is out of service.

The two groups rely on local contacts to smuggle information out of IS-held territory.

U.S.-backed Syrian Kurdish forces are battling IS near the militant-held dam as part of a broader campaign to take Raqqa.

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2 p.m.

A leading Syrian opposition group is calling on the U.S.-led coalition to stop targeting residential areas in and around Raqqa, the Islamic State group's de facto capital.

The Syrian National Coalition says it is "increasingly concerned" about civilian casualties in the campaign against the extremist group. The exiled opposition coalition is taking part in U.N.-mediated talks in Geneva.

The SNC says it believes coalition forces were behind an airstrike that killed at least 30 civilians sheltering in a school in the countryside outside Raqqa on March 21. The coalition has said it is investigating.

The U.S. has provided substantial air and ground support to the Kurdish-led Syrian Democratic Forces, who are closing in on Raqqa.