Britain changed its advice for tourists heading to Madagascar on Saturday following violence which left at least 28 people dead to warn against all travel to the island.

"We have raised the level of our travel advice to advise against all travel," a statement from the Foreign Office said.

"Following a reported upsurge in violence on Saturday 7 February, we are monitoring the situation in Madagascar closely."

Police in Madagascar, off the coast of Mozambique in southeast Africa, shot dead at least 28 supporters of opposition leader Andry Rajoelina Saturday as the protestors tried to march on the palace of President Marc Ravalomanana.

The island has seen weeks of violence amid a struggle for power between Ravalomanana and Rajoelina, former mayor of capital city Antananarivo.