Police in the northern Nigerian city of Kano, which is reeling from a wave of attacks that killed at least 160 people last week, said they found eight cars packed with bombs on Monday.

"We have discovered eight bomb-laden cars in different areas of the city," a senior police officer told AFP on condition of anonymity. "We are still facing serious security threats."

Residents of Kano said on Sunday a bomb-laden car was found abandoned outside a government-run fuel station but that the explosives were defused by police.

The bombs found on Monday were all home-made and were left in cars abandoned by roadsides in the city, the police official said.

On Friday, bombs were set off and gun battles raged in coordinated attacks launched after Muslim prayers in Nigeria's second largest city, with a police headquarters and other police stations, a secret police building and immigration offices targeted.

A purported spokesman for the Boko Haram Islamist sect claimed responsibility for the attacks, saying they were in response to a refusal by the authorities to release its members from custody.