Kenyan police said Sunday they were offering a reward for information about a car reportedly used in the attack on a Nairobi mall last month.

Police believe the car contained explosives and are offering a reward of 500,000 shillings ($5,827, 4,300 euros).

Britain on Saturday denied claims by Somlia's al-Qaida-linked Shebab that British special forces were involved in an attack on a key insurgent base.

A spokesman for the Islamist group said "Britons and Turks" staged the operation in which commandos rappelled from a helicopter as they tried to storm a house belonging to a senior Shebab commander in the southern Somali port of Barawe.

Kenyan police said Saturday that only between four and six armed men, not 10 to 15 as earlier thought, conducted the September attack on a Nairobi shopping mall that left 67 dead.

"From what we have now that is coming out of the investigation, the number of attackers was between four to six," police chief David Kimaiyo told Kenyan television station KTN.

Police and security forces patrolled the streets of Mombasa Saturday, a day after Kenya's port city was rocked by deadly riots sparked by the assassination of a Muslim cleric.

After furious street battles on Friday in which four protesters died -- three from stab wounds and one shot -- and a church was torched, the city was largely quiet overnight and remained so Saturday, police said.

Four rioters died and a church was torched amid gunfire Friday, as police in Kenya's port city of Mombasa quashed protests sparked by the killing of a Muslim cleric.

Battles broke out as armed paramilitary police moved towards a mosque, whose leaders have been accused of links to Somalia's Islamist Shebab, insurgents who massacred 67 in Nairobi's Westgate shopping mall last month.

Four police officers who risked their lives to save victims of the Westgate mall siege in Nairobi will receive special recognition and promotions, a spokesman for Kenya's police chief said Wednesday.

"It is just one way of boosting their morale and that of their colleagues," Masoud Mwinyi, spokesman for police chief David Kimaiyo said.

Somalia's Shebab Islamists threatened Wednesday to step up militant attacks against Kenya, after Nairobi refused to pull its troops out of Somalia.

The al-Qaida linked Shebab claimed responsibility for last week's attack on Nairobi's Westgate shopping mall, in which at least 67 people died, with 39 more listed as missing by the Red Cross.

Somalia's Shebab Islamists insisted Monday that no woman joined them in an attack on Nairobi's Westgate shopping mall, dismissing speculation that British 'White Widow' Samantha Lewthwaite took part in the massacre.

"We once again openly declare that no woman was involved at Westgate," Shebab said on Twitter, reiterating it had a policy of "not employing sisters for such missions".

At least 39 people are still missing after last week's brutal assault on Nairobi's Westgate mall by Islamist gunmen, the Red Cross said Monday.

The four-day bloodbath at the upmarket shopping mall, which Kenyan forces brought to an end on Tuesday, left at least 67 people dead.

Britain on Saturday said a sixth British citizen had been confirmed dead in the four-day siege at a Nairobi shopping mall by Islamist gunmen.

"A sixth British national has been identified amongst those killed in the tragedy in Nairobi. We are providing consular assistance," a Foreign Office spokesman said.