A Syrian-based member of the Islamic State (ISIS), who authorities claimed had a direct link to the ringleader of the Paris bomb attacks, was killed in an airstrike in Syria a day before Christmas, U.S officials said.

Nine other senior ISIS leaders were killed in the last few weeks during bombing campaigns by the coalition forces, the officials added.

"Ten senior ISIS leaders operating in both Iraq and Syria, including several external attack planners with designs on attacking Western targets, had been killed in airstrikes,'' according to Col. Steve Warren, spokesman for the coalition, CNN reported.

"I think any organisation that sees its middle and upper management degraded in this way is going to lose some of their synergy. It's difficult to command and control an organisation without the command and control personnel," Warren commented.

However, he noted that despite this, there is much more fighting to be done. "We have not severed the head of this snake yet, and it has still got has fangs," the spokesman said.

Charaffe al Mouadan, one of the slain ISIS leaders, was believed to be an operative closely linked to Abdelhamid Abaoud, the Belgian-born ring leader of the terror attacks in Paris, and was "actively planning additional attacks in the West.''

Abaaoud was killed in a police raid in the Paris suburb of Saint-Denis last month following the terror attacks in Paris on Nov. 13, 2015 which killed some 130 people, reports said.

A source told CNN that French investigators had not suspected al-Mouadan to be an ISIS leader but confirmed that he was in touch with the Paris plotters days before the attack. Investigators are still determining the role, if any, he played in the attacks.

The source also said that al-Mouadan was a close associate of Samy Amimour, one of the gunmen who stormed the Bataclan concert hall in Paris.

News on the slain ISIS leaders came amid stepped-up effort by the Obama administration to broadcast its success against ISIS.

In a meeting with his national security team at the Pentagon on Dec. 14, President Obama told military commanders that he wanted to see a better job of having the so-called "narrative" of the war on ISIS communicated to the American people, a senior defence official said.

In recent months, the coalition has killed other senior ISIS figures, such as Mohammed Emwazi, aka "Jihadi John." Before that, Abu Sayyaf, a senior figure in the group's oil and petroleum operations, was likewise killed in an airstrike.

ISIS has been weakened following air campaigns by both the coalition and Russia since September. The Pentagon said the number of ISIS fighters killed has increased considerably as Iraqi forces drove them out of Ramadi this week, seven months after occupying it.

ISIS forces in the capital of Iraq's Anbar province peaked at close to 1,000, the Pentagon estimates, but shrank to 300 or so as the final battle for control of the city began a month ago. Since then, U.S.-led airstrikes have killed at least 100 more, according to U.S officials.