KANDAHAR, Afghanistan (Reuters) - A suicide bomber killed 11 people, including nine police officers, in southern Afghanistan on Monday, a day after one of the deadliest attacks against foreign troops in recent weeks, officials said.

Violence has increased since last year in Afghanistan where the Taliban, ousted in a U.S.-led invasion in 2001, have made a comeback in their campaign to drive out foreign troops. Afghan and foreign security forces are frequently targeted.

Since the weekend, nine foreign soldiers have been killed in a series of separate Taliban raids, the deadliest week for foreign forces in recent months. Four NATO-led soldiers were killed in a roadside bomb attack on Sunday.

The latest bomber was on foot and detonated explosives attached to his body in a group of officers outside the main police headquarters in Lashkar Gah, the provincial capital of Helmand, on Monday, a local police official said.

Two civilians were also killed, the interior ministry in Kabul said in a statement. Another 29 people, many of them police, were wounded.

A would-be suicide bomber armed with a grenade killed a police officer guarding a compound in a separate attack in western Farah province on Monday, an official said.

The bomber was shot dead by other police as he tried to enter the compound and blow himself up, the official said.

Some 70,000 foreign soldiers under the command of NATO and the U.S. military, along with tens of thousands of Afghans in government forces, are struggling to defeat a resurgent Taliban.

The new U.S. administration plans to send an extra 17,000 soldiers this year to stabilize the country, which some Western politicians and analysts fear may slide back into anarchy.

U.S.-led troops overthrew the Taliban government after it refused to hand over al Qaeda leaders wanted by Washington for masterminding the September 11 attacks on the United States.

With the surge of violence and rising casualties among their troops, some Western nations are reluctant to send their soldiers into areas where the al Qaeda-backed group is most active.

(Writing by Sayed Salahuddin; Editing by Paul Tait)