NAIROBI, Kenya - Kenya's opposition threatened mass rallies Wednesday to stop a gathering of African foreign ministers in Nairobi because they were not consulted about the meeting.

Previous opposition rallies over the disputed Dec. 27 presidential election have turned violent, with police firing tear gas and live bullets to break up crowds. Dozens of people died.

Foreign ministers from the East African bloc known as IGAD were due in Kenya on Wednesday for talks the next day on the country's crisis. President Mwai Kibaki's government is chairing the meeting.

The opposition threatened to hold protests Thursday, but did not say where.

"The (threat of a) mass rally stands," said Ahmed Hashi, a spokesman for the opposition Orange Democratic Movement, adding that the party "will make sure that they do not meet here."

The election, which foreign and local observers say was rigged, returned Kibaki to power for a second five-year term after opposition leader Raila Odinga's lead evaporated overnight. The vote unleashed an explosion of violence that has killed more than 1,000 people and has devastated the country's economy.

Violence continued in western Kenya, scene of some of the worst postelection clashes.

Police said they fired to disperse hundreds of residents who had barricaded the gates of the police station in Litein, 145 miles west of Nairobi. Two teachers were killed.

In a forest nearby, officers retrieved 18 bodies with gunshot wounds and machetes cuts. They had been killed in four days of clashes between rival gangs which police stopped by throwing grenades.

Aside from clashes with police, much of the fighting has been between rival ethnic groups, with much of the anger aimed at Kibaki's Kikuyu tribe, long resented for dominating politics and the economy.

Odinga is demanding a new election, but Kibaki has refused, arguing his re-election was fair.

Supporters of Odinga say the IGAD meeting would be seen as a nod to Kibaki's government.

"This government is an illegitimate one and the arrival of the ministers means recognizing an illegitimate government," Hashi said. "Let them go elsewhere."

Last month, former U.N. Secretary-General Kofi Annan managed to bring together Kibaki and Odinga for peace talks, which continued Wednesday.

Anyang Nyongo, secretary-general of Odinga's party, said Annan had told opposition leaders that no meeting of the IGAD would take place without the knowledge of Odinga's party.

"It has been agreed that ministers can only come with the agreement of both parties," Nyongo said. "They should not act unilaterally as if things are normal. Things are not normal, we are trying to resolve a crisis."

With confidence shrinking in the East African country, the U.S. Peace Corps said it was temporarily pulling out its remaining 58 volunteers, and there were fears that other organizations -- aid groups and businesses alike -- could follow suit.

The crisis "has significantly damaged the domestic economy," Global Insight, a U.S. consulting company, said in a report released Tuesday, downgrading its prediction for growth in 2008 to 4 percent from 6.1 percent.

Major foreign companies and aid groups have long used Kenya as a base for their Africa operations, helping make the country a regional economic powerhouse.

On Tuesday, Annan met with 300 business leaders who urged the politicians to end the violence, as the business community has done repeatedly since the outset of the crisis.

The Kenya Private Sector Alliance estimates that over the next six months up to 400,000 Kenyans are likely join the ranks of the unemployed. It also projects that businesses will lose up to $3.6 billion over the next six months, even if the crisis is resolved immediately.