By Aaron Ross

KINSHASA (Reuters) - Police in Congo's capital Kinshasa fired tear gas on Saturday to disperse opposition supporters seeking to defy a ban on public protests and rally against plans by President Joseph Kabila to stay in power beyond the end of his mandate this year.

Police officers in riot gear and armored trucks patrolled the perimeter of the field where opposition leader Etienne Tshisekedi was meant to address supporters.

Outside Tshisekedi's house in the nearby district of Limete, police fired tear gas to disperse small groups of opposition supporters, witnesses said.

"The police shot tear gas at the activists near the entry to Limete," said Bienvenu Bambale, one of several opposition leaders milling about outside Tshisekedi's house, adding that the rally had been canceled so as not to risk violence.

The signals of French broadcaster Radio France Internationale and U.N.-funded Radio Okapi had been disabled on Saturday morning, as is often the case when the opposition protests.

Kabila, who succeeded his assassinated father in 2001 and went on to win disputed elections in 2006 and 2011, is required by constitutional term limits to step down on December 19.

But his ruling coalition and part of the opposition agreed last month to delay a presidential vote until April 2018, citing a lack of financing and logistical problems registering millions of voters.

The main opposition bloc, however, has rejected the accord and more than 50 people died in anti-government street protests in September.

Kinshasa's provincial governor banned all political demonstrations in the aftermath of September's violence and refused to be swayed by requests from the U.N. High Commissioner for Human Rights this week that peaceful protests be allowed.

Police spokesman Pierre Mwanamputu said on Saturday that police were dispersing all gatherings of more than 10 people but that the situation remained mostly calm.

While the rally's suppression marked a setback for an opposition that has generally struggled to mobilize large numbers in the streets, its leaders vowed new efforts to raise pressure on Kabila to quit power.

"On December 19, we will call all Congolese to chase Kabila from his palace," said opposition member Bambale.

International donors fear that the political impasse could reignite chaos in the Central African giant, where millions died in regional conflicts between 1998 and 2003 and which has never experienced a peaceful transfer of power.

In response, the United States has imposed financial sanctions against three generals for alleged human rights violations and the European Union is considering similar measures.

(Editing by Joe Bavier and Stephen Powell)