US and coalition airstrikes 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.

US Army Col Steve Warren told Pentagon reporters that the militants were killed mainly by drone strikes in Iraq and Syria. He offered few details, but said at least two of those killed were linked to the Paris attacks.

According to 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 last Thursday in Syria, was planning additional attacks against the West, Warren said.

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.

Warren's announcement came as Belgian authorities said they had arrested two men in connection with a suspected plot involving attacks during the holiday season in Brussels.

They said the plans involved attacks similar to those that hit Paris on November 13, when 130 people were killed and hundreds more wounded by suicide bombers and gunmen. The Islamic State group has claimed responsibility for the Paris attacks.

Al Mouadan, a 26-year-old Frenchman who grew up in the poor Paris suburbs, was arrested in France in October 2012, and was charged with "criminal association in view of preparing acts of terrorism," a sweeping charge often used by the French to nab potential terrorists.

He was not imprisoned and left for Syria in August 2013, where he joined the Islamic State group, according to a Paris judicial official.

The official said al Mouadan took the nom de guerre Abou Souleymane. The Paris official was not authorized to discuss the case, so spoke on condition of anonymity.

According to the official, the French investigation of the Paris attacks linked al Mouadan with longtime friend Samy Amimour, one of the three attackers at the Bataclan theater. Amimour was killed by police.