Zimbabwe's opposition party says four of its activists were found dead Thursday near Harare, one week before the country's runoff presidential election.
Officials from the Movement for Democratic Change provided few details about the four. There has been widespread violence in Zimbabwe since March's presidential election.
U.S Secretary of State Condoleezza Rice is scheduled to discuss Zimbabwe's political crisis before the U.N. Security Council Thursday.
Election officials in Zimbabwe say opposition leader Morgan Tsvangirai won more votes than President Robert Mugabe in the March election, but did not win enough for a majority.
The opposition accuses Mr. Mugabe's supporters of waging a campaign of violence and intimidation. The ruling party blames the opposition for the violence.
Western and African countries are increasing pressure on Mr. Mugabe to ensure the vote is free and fair.
South African President Thabo Mbeki held separate talks Wednesday in Zimbabwe with Mr. Mugabe and his challenger. There is no word on whether any progress was made in those talks.
U.N. Secretary-General Ban Ki-moon expressed "profound alarm" Wednesday at the situation in Zimbabwe. He said the violence, intimidation and arrest of opposition leaders could not lead to credible elections.
The U.S. House of Representatives passed a resolution Wednesday condemning the political violence in Zimbabwe. The House also passed another resolution praising dock workers in South Africa who blocked an arms shipment that was destined for Zimbabwe.
Mr. Mugabe has ruled Zimbabwe since 1980.
Some information for this report was provided by AFP and AP.