Interpol issued a wanted persons alert at Kenya's request on Thursday for Samantha Lewthwaite, a British citizen dubbed the "White Widow", without mentioning her suspected role in the Nairobi mall attack.
The international police agency's so-called "red alert" notice said Lewthwaite, 29, is wanted by Kenya on charges of possession of explosives and conspiracy to commit a felony dating back to December 2011.
Lewthwaite, also believed to use the alias 'Natalie Webb', is the widow of Germaine Lindsay, one of the Islamist bombers who carried out attacks on public transport in London in July 2005, and is thought to have left Britain several years ago.
South African Interior Minister Naledi Pandor told a news conference in Pretoria on Thursday that Lewthwaite had entered South Africa in July 2008 with an illegal passport, which she last used in February 2011.
She is wanted in connection with an alleged plot to attack luxury hotels and restaurants in Kenya.
British police have cited Lewthwaite as a possible suspect in last week's siege of a Nairobi shopping mall by Islamists from Somalia's al Shabaab movement.
Some witnesses said that women were among the attackers in the four-day mall attack, which killed at least 72 people. But al Shabaab denied on its Twitter feed using "our sisters" in its military operations.
An Interpol spokesman declined to say when Kenya lodged its request for the alert.
"Through the Interpol Red Notice, Kenyan authorities have ensured that all 190 member countries are aware of the danger posed by this woman, not just across the region but also worldwide," Interpol Secretary Ronald Noble said in a statement.
SEARCH FOR SUSPECTS
In Nairobi, experts from U.S., British, Israeli and other agencies have joined Kenyan officers investigating the Westgate mall attack. Police are also Ptracking four suspected militants in Kenya's coastal tourist region.
The high-impact attack has highlighted the reach of al Shabaab beyond Somalia, where Kenyan troops have joined other African forces, driving the group out of major urban areas, although it still controls swathes of the countryside.
"We have four suspects within Mombasa who we are closely watching. They came back to the country after training in Somalia," Robert Kitur, county police commander in the port city and beach tourist hub, told Reuters.
Western nations have long feared turmoil in Somalia was providing a training ground for militants. Kenya sent its troops into its northern neighbor in 2011 to fight the group it blamed for attacks along the border and kidnappings on the coast.
Highlighting the lawless nature of Kenya's northern region near Somalia, two policemen were killed on Thursday in an assault on a administrative post in that region. Al Shabaab said its fighters carried out this latest raid.
Part of the Westgate mall collapsed in the four-day siege that followed Saturday's attack, burying some bodies and hindering investigations, although forensic experts have started work even as the army continues to comb the building for explosives.
"The army are still in there with the forensic teams," said one senior police officer near the mall that was crowded during lunchtime on Saturday when attackers armed with assault rifles and grenades stormed in.
Officials say the death toll of 61 civilians, six members of the security forces and five militants is unlikely to rise much further, although some bodies of the attackers may be buried.
However, the Red Cross has said there were still 71 people listed as missing.
Several details of the attack remain uncertain: the final death toll, the identities of attackers, how many there were - officials indicate about a dozen - and how they staged such a sophisticated raid that lasted so long.