Coalition air strikes have killed 10 Islamic State leaders over the past month, including several linked to the Paris attacks or other plots against the West, a US military official in Iraq said.

They were killed mainly by drone strikes in Iraq and Syria, US army Colonel Steve Warren said.

He offered few details but said at least two of those killed were linked to the Paris attacks.

He said one was directly tied to those who planned the violence in Paris and was actively planning other assaults against the West. Most appeared to be mid-level leaders.

Col Warren said that one of the others killed was from Bangladesh but spent time in Britain and was a hacker for IS and co-ordinated anti-surveillance technology.

According to Col Warren, one of the insurgents killed was Charaffe al Mouadan, a Syrian-based IS member who was directly linked to Abdel Hamid Abaaoud, the Paris attack cell leader. Mouadan, who was killed by an airstrike in Syria on last Thursday, was actively planning additional attacks against the West.

Also killed was Abdel Kader Hakim, who was part of the Islamic State group's effort to plan attacks against Western targets and "had links" to the Paris attack network, Warren said.

Most of the 10 appeared to be mid-level leaders.

"We're striking at the head of this snake," Col Warren said. "We haven't severed the head of the snake yet, and it's still got fangs. We have to be clear about that. There's much more fighting to do."