Kenyan and Somali troops jointly attacked al Shabaab hideouts in Somalia on Thursday, killing a number of militants, and a Kenyan soldier was killed by a roadside bomb while on patrol elsewhere along the border warzone, officials said.

The fighting was the latest action since Kenya ordered soldiers across the border in October to crush al Qaeda-linked al Shabaab rebels who it said had attacked its security forces and tourists inside Kenya.

Although there appears to be little progress on the ground in Somalia as torrential rains have bogged down operations, more airstrikes have been launched on al Shabaab strongholds in recent days and skirmishes and bomb attacks in northern Kenya.

Kenyan army spokesman Emmanuel Chirchir said Kenyan and Somali soldiers backed by helicopter gunships attacked and destroyed al Shabaab bases in Hawina town on Thursday, a day after Kenyan war planes bombed two Islamist militant bases in Somalia near the town of Badade.

A senior Somalia officer said a number of militants were killed and several captured during the strike.

We attacked today, together with our Kenyan allies, an al Shabaab base in Dalbes jungle, between Hawina and Tabda. Before our infantry got in, helicopters bombed the whole area, Abdikarim Ali Yusuf told Reuters from Tabda in southern Somalia.

In the Kenyan frontier town of Mandera, a roadside bomb killed one Kenyan soldier and wounded four while they were on patrol in a truck on Thursday morning.

A huge fire engulfed the truck, residents said. Five wounded were airlifted to Garissa for treatment but one subsequently died.

I heard a heavy explosion...I saw smoke. The truck was burning and was reduced to a shell, said Ibrahim Mohamed. I saw three officers on the ground, they were all crying out. Their bodies were blood-stained.

Residents said the army had rounded up people in Mandera town following the blast, although Chirchir denied this.

Kenyan Colonel Cyrus Oguna said it was too early to say whether the attack was the work of al Shabaab or bandits.

Garissa, a town in northern Kenyan, is an important military base, from where ground forces have been deployed across the frontier into Somalia.

Kenya is the latest foreign power to try to stabilise Somalia, which has been mired in violence for two decades since the overthrow of dictator Mohamed Siad Barre in 1991 allowed first warlords, then Islamist militants, to step into a power vacuum.

Al Shabaab, fighting to impose a harsh interpretation of sharia law, has said it take revenge against Kenya.

(Additional reporting by Sahra Abdi and James Macharia in Nairobi and Mohamed Ahmed in Mogadishu; Writing by James Macharia; Editing by Angus MacSwan)