ISIOLO, Kenya (Reuters) - Four Kenyan school children were killed in a gunfight on Tuesday between police and al Shabaab militants from Somalia who attacked a telecommunications mast in the third such deadly incident in Kenya this week, police and an official said.

A Kenyan police officers walks in the rain in downtown Nairobi, Kenya January 7, 2020. REUTERS/Njeri Mwangi

Officers killed two attackers and recovered two assault rifles and bomb-making materials, police spokesman Charles Owino said.

Owino told Reuters in a text message that the four killed were school children. He had said in a statement earlier on Tuesday that a teacher was among the dead.

“I console the families of the four pupils that were killed by the heartless terrorist militia who are hell-bent on slaying innocent lives, instilling fear and disrupting education in the region,” Garissa County Governor Ali Korane said in a statement.

The attackers also wounded three other children, Mohamed Dubow Aden, Garissa County’s Red Cross coordinator told Reuters.

Aden said three of the dead children were from one family.

The United States has sent more troops to Kenya to reinforce security after al Shabaab killed three Americans on Sunday in an attack on a military base in Kenya used by U.S. forces.

In Tuesday’s attack, police said militants fired at a mast belonging to Kenya’s leading operator Safaricom and at police guarding the facility.

“Officers manning the mast and the base together with special forces were able to repulse them,” police said.

The raid took place in a village in eastern Garissa county, which neighbors Somalia. The attackers did not damage the telecom network, police said.

Al Shabaab frequently carries out attacks in Kenya in retaliation for Kenya sending troops into Somalia in 2011 after a series of cross-border attacks and kidnappings.

The Kenyans were later absorbed into an African Union peacekeeping force, now 21,000-strong, which supports the shaky, Western-backed Somali government.

Al Qaeda-linked al Shabaab has waged an insurgency in Somalia since 2008, aiming to topple the government and impose its own strict interpretation of Sharia law.

On Sunday, al Shabaab destroyed six aircraft and killed three Americans during the attack on Camp Simba in coastal Lamu country. On Thursday, the insurgents killed three civilians on a bus in the same county.