The main opposition candidate in Ghana's presidential election had 48.5 percent of votes with almost all counted on Sunday, and the contest seemed likely to go to a second round, Electoral Commission sources said.

At least seven people died in the northern town of Bawku after a dispute over ballot boxes degenerated into ethnic clashes.

The commission sources said certified results for 192 out of 200 constituencies showed that John Kufuor, leader of the New Patriotic Party (NPP), had failed to clinch an outright victory in the race to succeed President Jerry Rawlings, who is stepping down after 19 years in power.

Kufuor's closest rival, Vice President John Atta Mills, obtained 44.5 percent of the vote, the sources said.

The remaining votes from Thursday's poll were split among five other candidates.

The Electoral Commission said late on Saturday it would release the final results on Sunday afternoon.

The sources said the eight constituencies for which results had yet to be certified included two constituencies in the Volta region, a stronghold of the ruling National Democratic Congress (NDC), and two in the Ashanti region, where the NPP draws the bulk of its support.

In the remaining constituencies, party allegiances were less clear-cut.

A second round must be held within 21 days of the first if no candidate gets more than 50 percent of the vote.

In the parliamentary election also held on Thursday, the NPP was ahead with 94 seats against 73 for the NDC, the sources said. The release of parliamentary election results was delayed in some constituencies, including Bawku.

The NPP said on Sunday it remained confident Kufuor would clinch an outright victory. The NDC disputed that, saying results in its possession showed a run-off was likely.

Rawlings, who seized power in a military coup but won multi-party elections in 1992 and 1996, is due to step down on January 7 under a constitutional two-term limit. He has pledged to respect the poll result.