Antananarivo - Security forces in Madagascar fired warning shots and tear gas on Monday to repulse a crowd of stone-throwing opposition protestors who gathered near government buildings to press for the installation of a new administration

The standoff took place near the central May 13 square in the capital Antananarivo, when around 10,000 people answered a call by self-proclaimed national leader Andry Rajoelina to usher in his "ministers."

Rajoelina on Monday presented two new ministers to his line-up of 12 ministers, which he says should replace President Marc Ravalomanana's elected government.

A group of protesters broke away from the rally and attempted to march on the ministry of youth and sport, but their path was barred by a cordon of around 200 heavily-armed police and soldiers.

The security forces fired tear gas and shots over the heads of the protesters, who lobbed stones at them. No one was reported injured.

Tensions are running high on the impoverished Indian Ocean island since guards at the presidential palace opened fire nine days ago on unarmed opposition supporters, mowing down 28 people.

The showdown between Ravalomanana and Rajoelina, whom the government sacked as mayor of Antananrivo last month, began in earnest in December when the state shut down Rajoelina's TV station.

Over 100 people have been killed in the subsequent string of demonstrations, strikes and riots.

In laying siege to the presidency, and now government, Rajoelina, who is calling for Ravalomanana to be stripped of his powers, is following the president's own example.

In 2002, ex-Antananarivo mayor Ravalomanana led months of strikes and demonstrations that forced long-time leader, Didier Ratsiraka, from office.

Ravalomanana's campaign had its roots in the previous year's presidential elections, which he said he won. Rajoelina's grab for power, by contrast, has no election basis.

The former DJ accuses the president of clamping down on civic freedoms and of mismanaging scarce public funds. Most Madagascans struggle to get by on less than a dollar a day.

Ravalomanana, a business tycoon, who was re-elected to a second five-year term in office in 2006, has rejected the calls to step down as anti-constitutional.

A team of negotiators led by United Nations special envoy Haile Menkerios are brokering talks between the two camps. (dpa)