The Home Ministry on Monday issued an alert for Mumbai, Kolkata and Bangalore saying the three major cities could be targeted by terrorists.

The 20 men are wanted in connection with a case registered by the Federal Investigation Agency and have been booked under provisions of the Anti-Terrorism Act, Pakistan Penal Code and a cyber crimes law.

Five operatives of the Pakistan based militant group JeM, including its Pakistani coordinator in Bangladesh who was also a recruiter for operations in India, was nabbed in Dhaka on Sunday, officials said.

In stepped-up US attacks on militant hideouts in Pakistan, a drone rammed missiles on a compound in a restive North Waziristan tribal region on Sunday killing at least 15 terrorists, mostly foreign fighters.

The indictment of David Headley for involvement in planning the 2008 Mumbai terrorist attacks shows Pakistani terror group Lashkar-e-Taiba (LeT) too has global ambitions and is willing to undertake bold, mass-casualty operations, according to a top US counter-terrorism official.