Terror suspect Samantha Lewthwaite has been linked with the failed grenade attack on British tourists in Kenya.
The Muslim convert, dubbed the White Widow, is accused of ordering the attack on the tourists who were travelling to a wildlife safari at the Masai Mara national park.
The grenade failed to detonate when it hit the window of the Toyota 4X4. It is believed to have been thrown by a man, who later fled the scene.
The grenade was later safely detonated. The Foreign Office said it was urgently looking into the reports.
Lewthwaite, 29, who is already accused of plotting to kill hundreds of British tourists in Mombasa with fellow British accomplice Jermaine Grant in a separate attack, has now been linked to the incident.
A senior security source in Kenya told the Daily Mirror: "It's the two-year anniversary of Lewthwaite going on the run and intelligence reports suggest she may have ordered the attack.
"She is being hunted on multiple terror charges and we know her links to al-Shabaab fanatics spread through Africa.
"This was a deliberate attempt to kill tourists and has all the hallmarks of a White Widow-instigated operation."
Kenya has seen a number of grenade attacks since 2011, when it invaded southern Somalia to try and oust al-Shabaab insurgents.
Lewthwaite, originally from Aylesbury, Buckinghamshire, was named the most wanted woman in the world after being linked to the Westgate shopping massacre in Nairobi in which 70 people were killed.
A grenade attack in Kenya which killed three football fans who were watching the Italy vs England Euro 2012 game has also been linked to Lewthwaite.
The widow of 7/7 Kings Cross bomber Germaine Lindsay, Lewthwaite was arrested with her accomplice Grant in 2011 but escaped along with her three children. She has been on the run in Africa ever since. She is currently believed to be hiding in Somalia.
Following the grenade attack, Mombasa police say they have strengthened security in the area.
Mombasa's police chief Robert Kitur said: "We are appealing to everybody to exercise caution, especially over this festive season, and to share information with security agencies to win the war on terror.
"We have intensified security at tourist hotels and other vital installations to avert terrorism attacks."