|Tshisekedi, pictured, announced he would give a "very large reward" to anyone bringing him Kabila "tied up" [AFP]
Joseph Kabila has been sworn in for another five-year term as the Democratic Republic of Congo's president even as his main rival, Etienne Tshisekedi, continued to lay claim to the same job following disputed polls in the central African nation.
The 40-year-old incumbent was confirmed the winner of November polls, which the country's opposition parties and international observers say were rigged.
Kabila took the oath vowing to "safeguard national unity and allow himself to be guided only by the general interest and the respect of human rights".
The presidential vote in Africa's second-largest country was criticised by poll observers and by Tshisekedi who has proclaimed himself the country's president and is planning his own inauguration on Friday.
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The 79-year-old Tshisekedi has stopped just short of calling for mass protests and urged the security forces to defect and recognise him as the elected president.
The opposition leader, a former prime minister under Mobutu Sese Seko, has no militia of his own, but the announcement of the results earlier this month triggered violence in the streets of Kinshasa with angry supporters clashing with security forces.
Police were heavily deployed across the capital on Tuesday, particularly in the eastern Limete district where Tshisekedi's Union for Democracy and Social Progress (UPDS) is headquartered.
Opposition protesters were dispersed with tear gas there on Monday and several tanks from the Republican Guard were stationed across the city, according to the AFP news agency.
People protected by tanks
"It's for the people that these tanks are there," Lambert Mande, a government spokesman, told UN-supported radio Okapi on Monday. "It's to help their ease of movement and to protect important visitors."
Kabila, who took over in 2001 after his father Laurent-Desire's assassination, risks isolation on the international scene as a result of the election, which the West has condemned as fraudulent.
DR Congo's western trade partners were represented at Kabila's relatively low-level inauguration ceremony on Tuesday and the only head of state who attended was Robert Mugabe, Zimbabwe's president.
The United States has said the elections - just the second in the DR Congo since back-to-back wars from 1996 to 2003 were "seriously flawed", and Belgium and France have also questioned their credibility.
Observers fear the vast mineral-rich country, which is two-thirds the size of Western Europe, could be headed for a crippling institutional crisis, or worse, for a flare-up of civil unrest.
Tshisekedi in a speech this weekend urged Congolese citizens "not only to retain their calm and serenity ... but also to create the climate of confidence that investors are looking for".
But he has also said he will give a "very large reward" to anyone bringing him Kabila "tied up", a move some have dismissed as a publicity stunt as no one in the country can arrest Kabila.
Kabila's party spokesman, Aubin Minaku, brushed off the rhetoric, saying: "Yet another joke." He called Tshisekedi a "bad loser".