NEW DELHI - A day after issuing a terror alert for the holiday week, police in India's commercial capital of Mumbai launched a manhunt Friday for four terrorist suspects thought to have sneaked into the city.
"The police [are] on high alert all over the city. We cannot take any of these intelligence inputs lightly in the holiday season," said Nisar Tamboli, deputy commissioner of police in the Mumbai crime department. "Since yesterday, we are checking all the possible hideouts, small lodges and guesthouses, railway stations. We are checking all the vehicles that are coming into the city."
Mumbai was the site of a deadly three-day siege in November 2008 when gunmen attacked two five-star hotels, a train station, a cafe and a Jewish prayer center, killing more than 160 people.
At a news conference Thursday, Mumbai police said four suspects had sneaked into the city four days earlier to carry out terrorist attacks. Authorities released a hazy sketch of a bearded man called Walid Jinnah.
Holding up his image, senior police officer Himanshu Roy said the four men were members of the Pakistan-based militant group Lashkar-i-Taiba and were between 20 and 30 years old. He appealed to people to call police if they see any suspicious activity.
Roy did not share information about the nationality of the suspects or the route they might have taken to enter Mumbai. India's Ministry of Home Affairs has also issued an alert, saying the western cities of Mumbai and Ahmedabad are particularly vulnerable.
On Friday, police deployed in force at several crowded spots, government buildings and hotels in Mumbai.
"We are going to be on alert until the holiday week is over," Tamboli said. "If we are satisfied, we may withdraw the alert after the New Year celebrations."
This is the second time a terrorism alert has been issued in three months in Mumbai. In September, police released two pictures of suspects days before a popular Hindu festival during which tens of thousands of people dance and sing in the streets.
Relations with neighboring Pakistan have been strained since the 2008 attacks on Mumbai. India accused Pakistan's Lashkar-i-Taiba of engineering the assault. Indian police arrested the lone surviving gunman, who is now on trial in Mumbai. Earlier this year, a lower court sentenced the gunman to death, and he has appealed.
The Indian government wrote to Pakistani authorities Thursday seeking permission to question seven suspects in the case who have been jailed in Pakistan.
Two bombings have been carried out in India this year - one in the western city of Pune in February that killed 17 people and another this month in the Hindu holy city of Varanasi that killed a child. The attacks were attributed to homegrown militants. Neither case has been resolved.
A police official in Mumbai has warned four suspected militants of Pakistani origin have entered the city, the capital of Maharashtra, India, and claims they are plotting attacks in the city. Police are now searching for the four people, thought to be members of Lashkar-e-Taiba (LeT), the Islamic  militant group the Indian government holds responsible for the coordinated attacks which hit Mumbai in 2008. Joint police commissioner Himanshu Roy says intelligence suggests "the threat is serious."
Lashkar-e-Taiba are thought to be responsible for the coordinated attacks which hit Mumbai in 2008. 

A United States counter-terrorism official said the attacks are likely imminent, and will occur over the Christmas and New Year period. "There's no question LeT remains interested in pulling off another large-scale attack in India," the official said, speaking on condition of anonymity, "and we are alert to the possibility that LeT might again try a holiday attack."

Speaking at a press conference, Roy said "they have recently arrived in Mumbai. We are not in a position to reveal their nationalities now but they are LeT members."


Armed police have been posted around high-profile destinations in the city, and roads around the —seiged by militants in the 2008 attacks—have been closed. Police have released a sketch of one of the militants believed to be in the city.

"The police are on high alert all over the city. We cannot take any of these intelligence inputs lightly in the holiday season," another Mumbai official said. "Since yesterday, we are checking all the possible hideouts, small lodges and guesthouses, railway stations. We are checking all the vehicles that are coming into the city."

166 people died and hundreds more were injured in the 2008 attacks, in which multiple gunmen attacked the  railway station, a hospital, a police station, and numerous hotels, amongst other sites. The attacks were dubbed "India's 9/11" by local media. Only one militant survived the attacks, Ajmal Amir Kasab; in May this year he was sentenced to death by hanging, on 86 charges, including murder, terrorism, and waging war against India.