A British citizen was among 11 al Shabaab militants killed by Kenya Defence Forces in Lamu county on Sunday.
British newspapers say Thomas Evans, who hails from Wooburn Green in Buckinghamshire, joined al Shabaab in 2012.
Evans is believed to have converted to Islam when he was 19 years old and changed his name to Abdul Hakim.
The Guardian reported that he attempted to fly to Kenya in February 2011, when he was 21, but was stopped by counter-terrorism police at Heathrow.
He later flew to Egypt, saying he wanted to learn Arabic, but contacted his mother in January 2012 saying he had travelled to Somalia to join al Shabaab.
Daily Mail reported that his mother, Sally, had been supplying police with information about the 24-year-old who wanted to become a suicide bomber.
"I would rather have Thomas alive behind bars than dead in the middle of nowhere because he wouldn’t just die innocently but die doing something that he shouldn’t be doing," the 56-year-old said.
"And if he took other lives, how do you live with this? If he was a suicide bomber, how would I live with that?
Sally said she felt disappointed by authorities that failed to stop Evans from travelling to Somalia.
She said she was awaiting confirmation of her son's death and asked the press to respect her family's privacy.
KDF spokesman Colonel David Obonyo said Evans and key al Shabaab commander and leader of the 2014 Mpeketoni attacks, Lukeman Osman, were among those killed.
Data about Evans and pictures publicly available "point at him", Obonyo said on Sunday.
"This is a big victory for us and also a major setback for al Shabaab because now there is no mainstream commander in the Lamu area," he told Reuters.
Obonyo said another man apparently of Caucasian or Arab origin was among the dead, while the others killed appeared to be from the region.
On Sunday, Inspector General of Police Joseph Boinett said two white terrorists were among the 11 militants.
Boinett said a cache of weapons was recovered following the incident at a militant camp
The weapons include 12 AK 47 rifles, 49 AK 47 magazines, one PMK assault rifle, a rocket-propelled grenade and three hand grenades.
A video camera and two motorola radios were also recovered in the attack in which two KDF soldiers were killed.
Boinett said some of the militants went to Bulla Gollol near Hulugho and harassed locals but fled as security officers closed in on them.
He said ten non-local residents, suspected to have been the militants' targets, have been accounted for.
The police are expected to release an official statement on the incident.
Two KDF soldiers were killed when the al Qaeda-linked al Shabaab fighters attacked a military base in Baure area in Baragoni.
Al Shabaab confirmed the weekend attack, telling Reuters "many Kenyan soldiers were killed", without giving precise figures.
The group, which often cites a higher death toll than officials, gave no details about any al Shabaab members killed.