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ANTANANARIVO, April 27 (Reuters) - Madagascar's security forces stormed the Constitutional Court on Monday, firing shots in the air and arresting its head of security who was accused of inciting public disorder.

Army commander Charles Andrianasoavina said the detained man and three colleagues apprehended in the raid were suspected of trying to destabilise new President Andry Rajoelina's interim government and of shooting at demonstrators in the capital.

"We received information that it was him (Ralitera Andrianandraina) who was behind the stun grenades and shots fired at civilians and security forces in Antananarivo in recent days," Andrianasoavina told journalists.

Arms were found in the security chief's car, he added, and the government said in a statement that seven assault rifles, four pistols and a grenade were seized inside the court.

Tensions have escalated across the city of faded French colonial grandeur as supporters of ousted leader Marc Ravalomanana repeatedly defy a new ban on public protest to denounce Rajoelina's army-backed takeover of power.

At least five people were killed last week in street clashes that raised the spectre of a return to the unrest that killed 135 people, scared off tourists and worried foreign investors before Ravalomanana's departure. (Reporting by Alain Iloniaina; Writing by Richard Lough; Editing by Daniel Wallis)

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