"Neutralizing and eradicating" the "Islamic State" ("IS") is a goal all countries agree upon, France's top diplomat Fabius said in a Friday interview to the French RTL radio.

France is currently on the diplomatic offensive to boost the fight against IS, including closer military cooperation with Russia.

The international campaign in Syria should focus on targeting the IS command in the Syrian city of Raqqa, according to Fabius.

"For us it is one of the main military targets, even the main one, because it is the nerve center of Daesh, and the attacks against France were planned from there," Fabius said, using another name for the IS.

French and Russian military jets have bombed the IS de-facto capital in recent days.

The airstrikes are also targeting oil convoys leaving the group's territory. The illegal oil trade is one of the key sources of income for the Islamists.

Some of the oil is headed toward Turkey, Fabius said, following earlier accusation by Putin that IS has been selling its oil to Turkish buyers. At the same time, France believes that Moscow ally Bashar al-Assad is also buying the IS oil, the French foreign minister added.

Working with Syrian troops

In the Friday interview, Fabius said that Syrian government troops could contribute against the "Islamic State," but only after Assad leaves.

"There are two measures: the bombing, and there should be ground troops," he told RTL.

"The ground troops can't be ours, because that would be counterproductive, but the grounds troops could be at the same time Syrian Free Army forces, Sunni Arab forces and - why not - forces of the regime," he added.

This could happen "within the context of a political transition -- and only in this context," he later clarified to the AFP news agency.

On Thursday, the French President Francois Hollande and Russia's Vladimir Putin agreed to share intelligence about terror activity and military operations in Syria.

"What we agreed, and this is important, is to strike only terrorists and Daesh [Islamic State] and to not strike forces that are fighting terrorism. We will exchange information about whom to hit and whom not to hit," Hollande said in their joint press conference.

Putin signaled that Russia might consider joining the US-led coalition against IS.

Berlin joining the fight in Syria

Germany also announced its decision to join to the military campaign in Syria on Thursday. Berlin plans to deploy several Tornado reconnaissance jets, a refueling aircraft and a frigate to help protect the French aircraft carrier Charles de Gaulle.

The defense minister, Ursula von der Leyen, said that she expected a prolonged battle, but described the Berlin move as necessary.

"If we want to fight terrorism and the reasons people are fleeing, then we have to do so locally," the minister said.

Foreign Minister Frank-Walter Steinmeier said that Germany's willingness to help France and the US-led coalition was also a matter of defending Germany's reputation in the world.

"Not only did we express our condolences for the victims, but we also showed our solidarity," Steinmeier said.

dj/kms (AP, AFP, Reuters, dpa)