Nairobi, Kenya (CNN) -- Suspicion that a Norwegian citizen was involved in the deadly Westgate Mall attack in Kenya last month "has been strengthened" but is not yet confirmed, Norway's security service said.
The Norwegian citizen, said to be of Somali origin, is believed to have ties to Mohamed Abdikadir Mohamed, known as Ikrima, who is regarded as one of the most dangerous commanders in the Somali terror group Al-Shabaab.
The Norwegian security service, PST, said its investigations in Norway and Kenya were ongoing, and that despite some media outlets reporting a name for the possible Norwegian suspect, it was not ready to confirm his identity.
"It has not yet been determined whether a named Norwegian citizen actually took part in the attack or not," a PST statement said Friday.
"Based on the information that we have uncovered this far in the investigation, however, the suspicion of his involvement has been strengthened."
It has also not yet been determined whether the person in question is still alive, the statement said.
Kenyan counter terrorism sources said Norwegian intelligence services in Kenya were investigating both Ikrima and the Norwegian citizen and have spoken to the latter's sister in Norway.
But Trond Hugubakken, head of communications for the PST, told CNN on Saturday that the two Norwegian officers currently in Kenya are not investigating Ikrima, only the Norwegian citizen and his connections with Al-Shabaab, as they seek to establish whether he was in Kenya.
He said the citizen's name would be disclosed by Norwegian authorities only if he's confirmed to be one of the gunmen killed in the mall attack, or if they have sufficient evidence to issue an international warrant for his arrest.
Hugubakken said investigators were also questioning people in Norway.
Kenyan authorities suspect Ikrima, also wanted by the United States, of involvement with the Westgate Mall attack.
Al-Shabaab claimed responsibility for the bloody four-day siege at the upscale mall in Nairobi, where at least 67 people died.
The Islamist group claimed another deadly attack Saturday, this time in the town of Beledweyne, in central Somalia. Somali police officer Isac Ali Abdulle told CNN at least 20 people were killed in the suicide blast at a cafe, although other officials gave a lower death toll.
Mohamed Ibrahim Ali, deputy governor of Hiiraan province, said seven government soldiers were among the dead. Al-Shabaab said it was targeting Somali and Ethiopian army commanders in the area.
Target of U.S. raid
U.S. officials said Ikrima was the target of a raid earlier this month by U.S. Navy SEALs on an Al-Shabaab compound near the town of Baraawe in Somalia. It's believed that he escaped after the U.S. troops came under heavy fire.
A Kenyan intelligence dossier seen by CNN alleges Ikrima's involvement with Briton Samantha Lewthwaite, a terror suspect known as the "White Widow," in a foiled Mombasa attack in 2011 with Jermaine Grant, a fellow British citizen currently held in Mombasa on terror charges.
Kenyan intelligence sources say that Ikrima, who speaks six languages and grew up in Kenya, is the main "point person" between al Qaeda in Somalia and al Qaeda in the Arabian Peninsula, and that he has helped pinpoint Kenyan targets.
Friends of Ikrima who knew him from his time growing up on the Nairobi suburb of Eastleigh told CNN he traveled to Norway in 2003 and grew increasingly radicalized there.
The sources, who had kept up with him over the years, said Ikrima traveled in 2007 to London, where they lost contact with him. In 2008 they heard he was in Somalia, where he has been based since.
Arabic, English and Swahili are among the six languages spoken by Ikrima, and he studied French for two years at the Alliance Francais in Nairobi, his friends say.
Al-Shabaab's growing reach
The possible involvement of the Norwegian citizen in the Westgate Mall attack has highlighted concerns about the widening reach of Al-Shabaab outside Somali borders.
Kenyan counterterror sources told CNN that security camera footage of the attackers inside the mall shows them talking by cellphone to people apparently outside the mall -- who the sources believe were giving the gunmen instructions. Telephone intercepts have led all over the region, from Uganda to Somalia and even possibly to al Qaeda in the Arabian Peninsula, the sources said.
As for the Norway connection, many people have traveled from Scandinavia to Somalia to join Al-Shabaab, CNN terrorism analyst Paul Cruickshank said.
The leader of Al-Shabaab has been following a strategy aimed at transforming it from a regional insurgent outfit into a terrorist group, Cruickshank said.
Ikrima, who is thought to have spent four years in Norway, appears to be central to that strategy, he said.
He managed to escape the raid by U.S. Navy SEALs, "so the concern now is that his credentials really will be burnished in the jihadist community globally, and he will be emboldened to commit more attacks potentially in the region," Cruickshank said.
Ikrima told a western intelligence informant several years ago that one of his key goals was to carry out attacks back in the West, using recruits from Western nations who'd come to Somalia for training.
He is believed to be a key link figure between different terrorist groups including al Qaeda and al Qaeda in the Arabian Peninsula, and may have key intelligence on future plots.
Stig Hansen, a security expert based in Norway and author of the book "Al-Shabaab in Somalia," told CNN that if the Norwegian suspect is who he believes him to be, he lived in a small town in Norway but had connections with a wider group, not all of Somali origin.
He came to Norway at age 8 or 9 and stayed for a couple of years, during which time he gained Norwegian citizenship, Hansen said. He later returned to Somalia.
Al-Shabaab became quite popular among some Somali community groups in Norway from 2007 to 2009, Hansen said, "because they were wrongly seen as some kind of national resistance group."
Observers noticed contradictions between what the group said in its English- and Arabic-language messaging, he said, which contributed to ignorance within the diaspora about its real nature.
"But the terrorist attacks inside of Somalia made it easier for the wider ethnic Somali community to see that this was really a terrorist organization, and it distanced itself," he said, making it less popular now.
However, this development brought its own problems, Hansen said, and not just in Norway.
"What you have to look out for, also in the United States and the United Kingdom and all these other Scandinavian countries, are these small, small networks that are in one sense detached also from the Somali community leaders -- radicalized groups of youths and radical preachers, sheikhs, that go traveling around the various countries to try to incite," he said. "That's what we have to watch these days."
CNN's Per Nyberg, Tim Lister and Atika Shubert and journalist Omar Nor contributed to this report.