Eritrea is the largest foreign backer of fundamentalists who are fiercely resisting attempts by Ethiopia and the Somali government to pacify Mogadishu, the British daily quoted Jendayi Frazer, the US Assistant Secretary of State for African Affairs, as saying.

"No insurgency group can survive without support from neighboUring countries," said Frazer in Nairobi on Saturday night, just hours after becoming the highest ranking US official to visit Somalia for 14 years.

Ethiopia, which accused the fundamentalists of terror links, immediately signalled its military support for Somalia's weak Transitional Federal Government (TFG) while Eritrea sided with the fundamentalists by supplying training and weapons, according to a UN report.

But Frazer said Asmara was backing the remnants of the fundamentalists, in particular the hard-line Shabaab fighters who formed the core of the guerilla movement along with clan and warlord militias opposed to the government.

Frazer said while the "global fundamentalist network" was also supporting the Shabaab, Eritrea's sole motivation was "anything that will hurt" its southern neighbour.

"This is very much aimed at Ethiopia," she said.