Syrian government warplanes on Tuesday bombed the country’s northeastern city of Raqqa, the de facto capital of the Islamic State in Iraq and the Levant (ISIL) insurgency, killing nearly 100 people.

Britain-based advocacy group the Syrian Observatory for Human Rights on Wednesday raised the death toll in the bombing to 95, making it one of the deadliest attacks on the city of Raqqa in the past three years.

The raids struck a popular market near the city's museum, residential areas, an industrial area and reportedly destroyed the historic Al-Hinni mosque.

Activists told Al Jazeera that the Raqqa branch of the Syrian Red Crescent — the sister organization to the Red Cross — was in the process of transporting 65 corpses to a nearby hospital. An anti-ISIL activist group, Raqqa is Being Slaughtered Silently, said the death count was over 100 people with more than 120 injured.

Activists said the majority of victims were women and children, because the strikes targeted mainly markets and residential areas. It remained unclear how many militants were among those killed.

The Syrian regime has been targeting ISIL in Raqqa ever since the group seized the city more than a year ago, though it was not immediately clear what prompted Tuesday's unusually intense bombing.

A U.S.-led anti-ISIL coalition has also been targeting positions in Raqqa over the past few months, in an extension of strikes against the group in Iraq. Washington says it has not coordinated with Damascus, which it has sought to force from power for several years, despite their mutual enmity toward ISIL.

Outside air strikes from either faction have become commonplace in Raqqa, but an activist in the city who goes by the pseudonym Abu Khalil and supports the U.S.-led effort said the regime’s strikes are more feared.

“The coalition targets Daesh headquarters,” he said, using the Arabic acronym for ISIL. “The regime shells civilians.”

U.S.-led strikes, however, have also reportedly incurred dozens of civilian casualties.

Meanwhile in Iraq on Tuesday, ISIL blew up a Christian convent in the northern city of Mosul, which has been controlled by the group since June.

Residents living near the Al-Nasir convent said that fighters had arrived on Monday and instructed them to keep their windows and doors open in order to withstand blasts.

Most of the convent was destroyed in the explosion but no one was injured. The resident nuns had fled the city, along with most of Mosul's remaining Christians, when it was overrun by ISIL in the summer.

ISIL has frequently targeted Christians across the country, bombing their churches and killing clergymen. They have also targeted indigenous religious minorities across Iraq's north, including followers of the ancient Yazidi faith, forcing tens of thousands from their homes.

With wire services. Michael Pizzi contributed reporting.