A new wave of airstrikes targeting the Syrian city of Raqqa, the headquarters of the extremist Islamic State group and the focus of an international military campaign, killed at least eight people, including five children, Syrian opposition groups said Friday.

The strikes came as France's foreign minister, Laurent Fabius, declared that destroying the ISIS headquarters and "neutralizing and eradicating" the extremist group is the main objective of the international campaign.

It wasn't immediately clear who carried out the latest airstrikes. The city in northeastern Syria is the group's de facto capital and has become the focus of international airstrikes in the wake of the Paris terror attacks and the bombing of a Russian jetliner over Egypt's Sinai Peninsula. ISIS has said it was behind both the Paris attacks and the downing of the Russian passenger plane.

A Raqqa-based activist group that reports on ISIS, known as Raqqa is Being Slaughtered Silently, said Friday that most of the casualties in the latest aerial bombardment occurred when warplanes targeted the city's Heten School. The school, like others in Raqqa, has been taken over by ISIS.

The Syrian Observatory for Human Rights put the death toll at 12, including the five children. Conflicting casualty figures are common in the chaos of Syria's civil war, now in its fifth year.

Russia and a U.S.-led coalition that includes France have been pounding Raqqa.

An IS-affiliated agency, Aamaq, published a video purporting to show nighttime explosions that lit up the Raqqa sky. The video showed a building and several cars on fire, and a man crouching over the bodies of five children. The agency claimed the casualties and destruction were caused by Russian airstrikes that targeted civilian areas.

In an interview with RTL radio, Fabius said that destroying Daesh is an objective that all countries agree upon, referring to ISIS by its Arabic acronym. He spoke after a week of intense diplomacy capped by the French president's meeting with Russian President Vladimir Putin.

Francois Hollande has been on a diplomatic drive since the Paris attacks to increase cooperation in tackling ISIS, which holds large swathes of territory in both Syria and Iraq. The extremist group claimed responsibility for the downing of a Russian passenger plane over Egypt, when all 224 people onboard were killed, as well as the Nov. 13 attacks in Paris that killed 130 people.

Fabius said Putin agreed on the need to focus international efforts against the extremist group and that France is drawing up a map of other, moderate groups, to protect them from warplanes.

He also said the international coalition is focusing on oil convoys from the group's territory, which provide a crucial source of income. He said some of the trucks head toward Turkey, and France believes Syrian leader Bashar Assad is also a buyer — a charge the Syrian government has denied.