By Roch Bouka
BRAZZAVILLE (Reuters) - Police in Congo Republic fired teargas at opposition supporters and arrested around 10 of them on Friday ahead of a planned news conference by opposition candidates who say last weekend's presidential election was won fraudulently.
President Denis Sassou Nguesso, who has ruled the Central African oil producer for 32 of the last 37 years, won re-election in Sunday's poll with 60 percent of the vote, according to official results announced on Thursday.
Early on Friday, around 100 police officers were positioned outside of the headquarters of the opposition UPADS party in the capital Brazzaville's Diata neighborhood, where a coalition of five candidates was expected to announce their own poll results.
A Reuters witness saw police fire at least two teargas canisters at the crowd that had gathered there and force about 10 opposition supporters into vehicles.
An opposition representative told Reuters the scheduled news conference had been canceled.
The government spokesman was not immediately available for comment.
On Wednesday, the opposition coalition denounced alleged fraud during the polls. It said that its own results showed Sassou Nguesso headed for defeat and promised to make public its own vote tallies.
Retired general Jean-Marie Mokoko, a former army chief turned opposition figure who finished third in the election, called for a campaign of civil disobedience on Thursday, potentially setting the stage for protests.
In a statement late on Thursday, the U.S. State Department advised all parties to remain calm and asked that any challenges to the results be made in compliance with Congolese law.
"The United States remains concerned about the transparency and credibility of the electoral process, including reports of irregularities, and the prolonged communications blackout," it said.
The government cut telephone and Internet communications ahead of the vote, a measure it said aimed to prevent unofficial election results circulating and causing unrest. Services were only restored on Thursday.
Congo's constitution was changed by referendum last year, lifting term and age limits that would have excluded Sassou Nguesso from running for another term in office.
At least 18 people were killed by security forces during opposition demonstrations ahead of the October referendum.
Congo's election has been watched closely across Africa, where several long-ruling presidents are trying to remove constitutionally mandated term limits so that they can stay in power.
(Writing by Aaron Ross; Editing by Joe Bavier)