Vote counting from the Philippine mid-term elections has been hindered by violence and reported fraud.
Millions of votes are being counted by hand
Two teachers died counting votes as their school was set alight on Monday night, bringing to 126 the number of election-related deaths, police said.
Meanwhile, observers spoke of voter intimidation and described seeing blatant attempts to buy votes.
The millions of votes from Monday's congressional and local elections are being counted by hand.
Initial results for local areas are expected as early as Thursday, but it could be weeks before the final outcome for the Senate and House of Representatives is known.
An exit poll by ABS-CBN television in Manila suggested that the opposition could win at least nine of the 12 Senate seats up for grabs.
But it is thought the 275-seat House of Representatives will remain in the hands of President Gloria Arroyo's supporters.
This would thwart any attempt by the opposition to launch a third bid to impeach her over allegations she fixed the 2004 presidential election.
National police chief, Oscar Calderon, described Monday's vote as "relatively peaceful", compared with the 189 deaths in the 2004 poll, but admitted there continued to be reports of "isolated incidents of violence".
Ballot boxes were set alight as teachers counted votes in a school south of Manila. The flames quickly engulfed the building, killing two and hospitalising three others, police said.
The election campaign was colourful, but often violent
TV reports also said a policeman guarding ballot boxes in northern Ilocos Norte province was shot dead after polls had closed on Monday.
At least three people were killed on polling day itself.
Mr Calderon vowed to go "hammer and tongs" against the perpetrators of violence over the last three months of campaigning, and "give justice to the 126 killed".
Meanwhile, election observers described seeing scenes of violence, intimidation and threats towards voters.
One volunteer observer in the south of the country told the Associated Press that she had seen vote-buying take place at the polling station - with ballot papers handed to voters with money attached.
"We... also talked to minors who were able to vote several times. We also saw people who already voted several times and had more than one ink mark on their fingers," Jessica Tulloch, a Chicago volunteer with the United Methodist Church, said.
The Asian Network for Free Elections warned of a "culture of impunity for election and political crime" that could "fuel calls for alternative government that can provide justice for the people".
But officials said that, while there were sporadic reports of irregularities, this poll had generally been more fair and peaceful than past elections.
"It is a credit to the Filipino people that [Monday's] elections, compared to previous ones, were generally peaceful and that we had a good turnout," presidential spokesman Ignacio Bunye said.
More than 70% of the country's registered 45 million voters are believed to have turned out for Monday's vote.
In total, about 87,000 candidates were contesting nearly 18,000 positions.