Preparations for Pakistan's Independence Day celebrations have been shattered after a suicide bomber blew himself up and killed at least five people.

At least a dozen more were wounded in the blast outside a mosque in Lahore late on Wednesday.

There was no immediate claim of responsibility but security officials said the blast was very likely in revenge for a Pakistani offensive against Taliban fighters in a tribal area bordering Afghanistan.

Shaukat Javed, the provincial police chief who said police were guarding the mosque near a police station when the blast happened, said two police officers and three civilians were killed.

The attack came as Pakistanis poured on to the streets before midnight to celebrate the 61st anniversary of the nation's independence, which falls on Thursday.