NAIROBI - A mob torched a church in western Kenya on Tuesday killing up to 30 people sheltering inside as post-election violence swept the east African country, witnesses said.

Ethnic clashes have rocked Kenya since President Mwai Kibaki's disputed re-election on Sunday. At least 150 people have died nationwide, and the death toll looked sure to rise.

"I saw about 10 to 15 bodies crammed in a corner. They were charred, I could not look at the scene twice," one local reporter who visited the scene told Reuters from Eldoret town.

"There was a part of the church where I could not access but the death toll could be about 25."

The reporter said about 200 people had been seeking refuge at the Kenya Assemblies of God Pentecostal church, about 8 km (5 miles) from Eldoret in fertile Rift Valley Province.

He said the victims were mostly Kikuyus from Kibaki's ethnic group, who fled homes in the area in fear of their lives.

"Some youths came to the church. They fought with the boys who were guarding it, but they were overpowered and the youths set fire to the church," he said.

Another local journalist in Eldoret who spoke to witnesses said up to 30 bodies lay in the church, and four were outside.

The area is multi-ethnic but traditionally dominated by the Kalenjin tribe. It suffered ethnic violence in 1992 and 1997 when hundreds of people -- mainly Kikuyus -- were killed and thousands more displaced in land clashes.

A senior security official in Rift Valley said a mob had burned down the church, adding that as many as 15,000 people were sheltering from the latest violence at churches and police stations in Eldoret town.

He said the opposition was to blame for incitement.

"We have lived together for years, we've intermarried, we have children, but now they've asked them to turn against them," the security official said. "We don't do this in Kenya. It is what happens in Yugoslavia and Sudan."

The grisly event in Kenya revives memories of Rwanda, where thousands were massacred seeking shelter in churches during the 1994 genocide that killed 800,000 people.

Before the reports of the church attack, the government said it was concerned about the situation in the region.

"We are worried about some sections of the Rift Valley where we know people are being organised by people who support a certain political persuasion to try and destabilise the country," spokesman Alfred Mutua told journalists.