Kenya"s Chief of the Defence Forces (CDF) General Julius Karangi
Gen. Julius Karangi, Kenya"s chief of the defense forces, speaks at a media briefing at his agency's headquarters in Nairobi on Oct. 29. REUTERS

Suspected Somali gunmen attacked a police station and a government vehicle in northern Kenya late on Monday, the latest in a series of assaults on Kenya since it sent troops to fight Somalia's Islamist rebels.

Kenya mounted an air and ground offensive against al Qaeda-linked al Shabaab in Somalia more than three weeks ago after a string of kidnappings and cross-border raids it blamed on the group.

While there has been little major ground combat within Somalia since Kenya forces entered the Horn of Africa nation, Kenyan authorities and al Shabaab fighters have claimed successes in attacks either side of the border.

Al Shabaab fighters attacked a Kenyan police station near the border town of El Wak late on Monday, said Kenyan police, Somali government forces and residents.

Mahmoud Ali Shire, commander of Somali government troops fighting alongside Kenyan forces, told Reuters two al Shabaab fighters had been killed in the gun battle.

Leo Nyongesa, the police commander of Kenya's North Eastern Province, said he was not aware of any Kenyan casualties.

Our officers were vigilant ... they fought the attackers. A team of military and police close to the border joined them and repulsed the thugs, who ran back into Somalia, he told Reuters.

Further to the south, gunmen attacked a Kenyan government vehicle ferrying exam papers to the border town of Liboi.

Gunmen ambushed the car and exchanged fire with a police escort, but no one was hurt, North Eastern Provincial Director of Education Adan Sheikh told Reuters.

REFUGEES PROTEST AGAINST AL SHABAAB

Monday's incidents were the latest in a string of low-level but persistent attacks on north-east Kenya. Two people were killed in a grenade attack in the military town of Garissa on Saturday.

A U.N. aid convoy also struck a landmine that failed to detonate in the Dadaab refugee camp, the world's largest, where 400,000 Somalis are living after fleeing violence and famine in their own country.

Thousands there demonstrated on Tuesday against al Shabaab and in support of Kenya's military action.

We are tired of staying away from our homes, our country. These thugs must be challenged and fought, Kusow Abdi Nun, a spokesman for a group of refugees from Hagadera, one of three camps within Dadaab, told Reuters.

They should stop using Islam to achieve their selfish interest, he said, referring to al Shabaab's aim of imposing their own strict version of sharia law across Somalia.

Kenya is the latest country to entangle itself in the affairs of its anarchic neighbour which has suffered two decades of civil war.

The military says it wants to eliminate the threat of al Shabaab, which has hit Kenya's crucial tourist industry, and help the Western-backed Mogadishu government which has been fighting the militants since 2007.

Kenya's military has vowed to launch more air strikes on al Shabaab's bases in southern and central Somalia, especially after reports that weapons consignments from Eritrea had reached an al Shabaab base there last week.

Eritrea strongly denies the allegations.