UPDATE 3-Senegal opposition vows to fight Wade re-election bid

* Capital Dakar calm after overnight riots, security raised

* Opposition threatens to make country "ungovernable"

* Youssou N'dour says Senegal becoming a police state (Adds comments from N'dour, Mouride spokesman, France)

By Diadie Ba

DAKAR, Jan 28 (Reuters) - Senegal's opposition threatened on Saturday to make the country "ungovernable" if President Abdoulaye Wade insisted on running for a third term in elections next month.

One policeman was killed during protests late on Friday, in which demonstrators threw rocks, overturned cars and burned tyres and security forces fired tear gas, after the country's top court said Wade had the right to seek a new term.

Calm returned to the capital Dakar on Saturday but security was boosted around the presidential palace, where truckloads of police in full riot gear were deployed, armed with tear gas grenade launchers and truncheons.

"Abdoulaye Wade has declared war on the people," Amath Dansakho, the head of the PIT party and member of the M23 opposition activist group, told reporters following a meeting with other political and civil society leaders.

"The decision that we have just made will prove to Wade that this is a country of free people. We will render the country ungovernable," he said.