Kenya's national police force confirmed on Thursday that 20 gunmen were killed and eight officers were injured in a suspected al Shabaab attack at the border with Somalia.

While patrolling in Mandera, a county that shares a border with Somalia, a special unit of police was attacked with "heavy" fire in an ambush which "left 20 militants fatally injured," according to the national police service on its official Twitter account.

"Police also recovered assorted weapons from the scene of crime," it added in its statement along with photographs of a heavy machine gun and rocket launchers.

SUSPECTED TERRORIST ATTACK IN MANDERA COUNTY.

Police in Mandera are investigating a suspected Al Shabaab terrorist attack following an ambush on our
Special Operations Group (SOG) team on July 5, 2023, at Ogorwen Location within Mandera County. pic.twitter.com/l3eAi14sjd

— National Police Service-Kenya (@NPSOfficial_KE) July 6, 2023

The Kenyan government announced that the planned reopening of the long-closed border with Somalia was delayed following deadly attacks blamed on the Al-Qaeda-linked militants.

Read next: 19 al Shabaab terrorists killed by Somali forces

All-out war

Kenya is considered a major contributor to an African Union force in Somalia in an effort to curb al Shabaab's ability to carry out fatal attacks.

Militant groups have been waging an insurgency against the central government for more than a decade. They managed to be active in parts of Somalia and other countries of the Horn of Africa, including Kenya, Ethiopia, and Djibouti.

They have carried out numerous attacks in the last years that have claimed hundreds of lives.

Earlier this month, the Somalian government confirmed that al Shabaab has requested negotiations after the army launched an "all-out war" against its militants.

Read more: US strikes alleged al Shabaab Somalia site, destroys unspecified arms