Medical officials say mortar rounds struck an anti-Islamist demonstration in Libya's second-largest city, Benghazi, killing three civilians and wounding at least nine.

The officials say Friday's shelling of nearly 1,000 protesters was the second deadly attack on an anti-Islamist rally this week.

Libya slid into chaos following the 2011 toppling and killing of dictator Moammar Gadhafi. The internationally recognized government is confined to the country's east, while a rival Islamist-led government holds the capital, Tripoli.

Friday's protesters were chanting against U.N.-brokered talks with Islamists and the special U.N. envoy for Libya.

Last month, Bernardino Leon condemned army chief Gen. Khalifa Hifter's military escalation against Benghazi's Islamists as "a clear attempt to undermine" dialogue, outraging residents.

The officials spoke on condition of anonymity because they are not authorized to brief reporters.