An Islamic State affiliate recently launched a series of violent assaults in West Africa, according to a British military publication that monitors terrorism and insurgency.

Over the past two months, ISIS has killed more than 150 African troops in Niger, Jane’s Defense Weekly reported. A Jan. 9 attack killed 89 soldiers, the publication said, noting that “the attack was the third major such operation since 10 December, with at least 174 Nigerien soldiers having been killed by militants operating under the Islamic State’s Wilayat Gharb Afriqiyya during the period.”

The attacks show the growing focus of ISIS on the Sahel region of Africa, and its loyalty to ISIS central leadership, the publication said.

The uptick comes at a time when the Pentagon is reviewing its deployments around the world and considering a possible drawdown of the roughly 7,000 U.S. troops in Africa.

“We’ve begun a review process where I’m looking at every theater, understanding what the requirements are that we set out for, making sure we’re as efficient as possible with our forces,” Secretary of Defense Mark Esper told reporters in December. Esper said yesterday that no decisions have been made but confirmed that he wants to shift resources to focus more on “great power” competition with Russia and China.

Members of Congress expressed concern over a potential Africa drawdown as the United States continues to fight terrorist groups like ISIS, Boko Haram, and al Shabab across the continent.

“These personnel and installations are critical in combating the ever-increasing number of violent extremist groups throughout the region that pose an immediate threat to our partners and allies in the region,” Republican Sen. Lindsey Graham and Democratic Sen. Chris Coons wrote in a letter to Esper last week. “In fact, there are at least a dozen terror groups with ties to either the Islamic State or al Qaeda operating in Africa.”

The group responsible for the recent attacks is known as the Islamic State in the Greater Sahara, according to the American Enterprise Institute’s Emily Estelle. It predominantly operates in northern Mali, Burkina Faso, and western Niger.

“ISGS attacks on hard military targets have grown noticeably more deadly since fall 2019. ISGS has not yet conducted an attack outside of its local area of operations, but it is developing capabilities that could allow it to do so eventually,” Estelle told the Washington Examiner.

ISGS is the same group responsible for a 2017 ambush attack that led to the deaths of four U.S. soldiers — Staff Sgt. Dustin Wright, Staff Sgt. Bryan Black, Staff Sgt. Jeremiah Johnson, and Sgt. La David Johnson. The troops were conducting a joint operation with Nigerian forces against ISIS at the time.

Responding to the concerns raised by Congress, Esper told reporters on Wednesday that “mission No. 1 is to compete with Russia and China,” per the Trump administration’s National Defense Strategy.

“I talk a lot to Congress, either to the committees or to individual members, and I do try and talk to the ranking members and chairs as often as I can,” Esper said. “Like I said, I think they’re just expressing their concern, which I appreciate. And like I said, as we continue to work our way through this process, we will consult and let them know what’s going on.”