Security has been tightened in major cities including Mumbai, the target of an attack in 2008 [Reuters]

India has stepped up security in many of its major cities, amid concerns that a Pakistan-based group is planning an attack over New Year's weekend.

More police were deployed to city streets on Tuesday, including in Mumbai, India's financial hub which was the scene of a three-day siege two years ago in which 166 people were killed.

Security was also tightened at airports and railway stations and the popular beach resort state of Goa.

An Indian home minister official, citing intelligence reports, said the banned Lashkar-e-Taiba group was planning to target such locations.

Security has been high in Mumbai since Friday, when police began searching for four men suspected of entering the city to carry out an attack.

Police later released computer-aided photographs of the four suspects.

Increased security

Friday's warning follows a bomb blast earlier this month at a Hindu temple in the city of Varanasi, which killed one and injured several others.

On Tuesday, police made house-to-house searches in some parts of the city and tightened security checks at bus and train stations, churches and markets.

In the 2008 Mumbai attack, 10 gunmen attacked two luxury hotels, a Jewish centre and a railway station. A member of the group which carried out the attack has been sentenced to death.

Pakistan has charged seven other people over alleged involvement in the attacks, but has not yet sentenced anyone.

In March, Mumbai police arrested two men who they said were preparing to hit several targets in the city, and in September police issued an alert for the city during a popular Hindu festival.