|Supporters of Democratic Republic of Congo's opposition leader Etienne Tshisekedi burn a tyre as they rally [AFP]
Congo's top opposition figure has urged the armed forces to obey him after losing elections he says were fraudulent.
Etienne Tshisekedi said on Sunday he would offer a "great prize" to anyone who captured President Joseph Kabila.
A close aide to Kabila dismissed Tshisekedi's comments as showmanship and said the opposition leader had made similar calls against former President Mobutu Sese Seko that had been ignored by the people.
However, the veteran politician's comments do threaten to escalate a row over the results of a November 28 presidential contest, which international observers say lacked credibility.
"I call on all of you to look for [Kabila] wherever he is in the country and bring him here alive," Tshisekedi said in his first news conference since official figures showed he was soundly beaten by Kabila.
"If you bring Kabila here to me you'll receive a great prize," he said, urging the armed forces to obey the country's "legitimate authority".
The president, who was thought to be in Kinshasa on Sunday evening, has broad support within the military, even though his rival is strongly backed by Kinshasa residents.
The election was meant to put Congo on a path to greater stability after decades of turmoil, but has instead deepened divisions.
Around 20 people were reported killed in clashes before and afterwards as opposition supporters took to the streets accusing the government of vote rigging.
'Seriously flawed' election
Observers have said the poll, Congo's second since a 1998-2003 civil war that killed more than five million people, was marred by irregularities, though Congo's election commission has said any problems did not affect the ultimate outcome.
"We as a government have followed every step of the constitution," Kikaya Bin Karubi, the Congo's envoy to Britain, told the Reuters news agency.
Kabila took around 49 per cent of the vote to Tshisekedi's 32 per cent, according to results ratified by Congo's Supreme Court on Friday.
Tshisekedi has rejected the outcome and declared himself president.
Kabila, who came to power after his father Laurent was killed in 2001, admitted last week there were "problems" with the election but said the legitimacy of the outcome could not be doubted.
The US ambassador to Congo called the election "seriously flawed" and US-backed observers from the Carter Center said results "lack credibility".
Congo is at the bottom of the UN's human development index and investors say it is one of the toughest places in the world to do business, despite its vast mineral riches.