Western countries are stepping up diplomatic pressure on Kenya as the death toll from post-election violence rises, and the country struggles to resolve disputes over President Mwai Kibaki's victory.

The United States and the European Union have voiced concern over the vote count in the race. And now, several members of Kenya's electoral commission are calling for an independent inquiry into the results.

Opposition candidate Raila Odinga and his party say the results of last Thursday's presidential election were rigged to make sure incumbent President Kibaki was the winner.

Police raids and tribal violence in the past few days have claimed the lives of at least 150 people. Some reports say the death toll is much higher.

A worker at a mortuary in the city of Kisimu said that more than 100 bodies were lying on the ground there.

Violence was also reported around Nairobi and in the city of Mombasa. Much of the violence appears to be ethnically-motivated, with members of Mr. Odinga's Luo tribe clashing with the Kikuyu tribe of Mr. Kibaki.

U.N. Secretary-General Ban Ki-moon appealed for calm in a statement issued late Monday. Mr. Ban also deplored the loss of lives and called on security forces to show restraint in dealing with protesters.

Both Mr. Kibaki and Mr. Odinga have also appealed for calm. But, Mr. Odinga is rejecting the official election results from the race and plans to hold a a peaceful mass rally in Nairobi's Uhuru Park on Thursday.

In his New Year's message, Mr. Kibaki appealed for "national healing" but said his government would "deal decisively" with rioters.

Early results from last week's (December 27) election had shown a big lead for the opposition challenger, but Mr. Kibaki surged ahead as the vote count was extended for two days.

Some information for this report was provided by AFP and Reuters.