Dec. 5 (Bloomberg) -- India broadened its security alert from airports to key government buildings and installations such as refineries after intelligence reports that terrorists may strike using a hijacked aircraft.

Security agencies in New Delhi sought increased checks for explosive devices around the federal parliament and buildings that house Prime Minister Manmohan Singh’s office among others, according to the police. Indian Oil Corp., the country’s largest refiner, has also stepped up security, a spokesman said.

The elevated alerts follow a purported e-mail threat sent by the Deccan Mujahedeen, which claimed responsibility for the attacks last week in Mumbai that left at least 195 people dead. India has blamed “elements” in Pakistan for the attacks, and is seeking to extradite 20 people.

“It is the obligation of all concerned to ensure that the perpetrators of this horrible crime are brought to book,” Singh said in New Delhi today at a joint press conference with Russian President Dmitry Medvedev, who’s visiting the country. “We will wait for the outcome.”

Airports were on alert for a second day, with security agencies profiling passengers before they board planes in Bangalore, Chennai and the capital, New Delhi.

Airport ‘Profiling’

“Profiling is being done outside the terminal and inside, with increased physical and hand baggage checks,” said Udayan Banerjee, deputy inspector general, Central Industrial Security Force, which oversees airport security.

“The coast guard and navy have increased security,” said B.C. Nayak, executive director for security at Oil & Natural Gas Corp., the country’s biggest exploration company. “We have also requested the Ministry of Defense to increase security in the sea, where ONGC has its operations.”

Security lapses led to last week’s terrorist attacks, Home Minister Palaniappan Chidambaram told reporters in Mumbai today.

India will need to maintain a heightened vigil for “months, maybe years,” said the minister, who took charge of the country’s security on Nov. 30, replacing Shivraj Patil, who quit after taking moral responsibility for the attacks.

The Mumbai police crime branch will lead the investigation into the attack, the minister said.

New Delhi Alert

An alert was triggered at the Indira Gandhi International Airport in New Delhi early today after passengers thought they heard gunshots. Airport operations returned to normal when police found no evidence shots were fired.

“Airports will be on red alert for a few days more,” Banerjee said.

The government received intelligence on the “possibility of aircraft being hijacked by terrorists,” state-run broadcaster Doordarshan cited Falil Homi Major, India’s air force chief, as saying yesterday in New Delhi.

A U.S. counterterrorism official said this week on condition of anonymity there are strong indications the Mumbai gunmen are linked to Lashkar-e-Taiba, a Pakistan-based militant group fighting Indian rule in the divided Himalayan region of Kashmir.

Terrorism analysts said Pakistan’s Inter-Services Intelligence Directorate has supported Lashkar and its operations over the years.

Not Enough Information

A U.S. counterterrorism official said today there isn’t enough information to show a link between the Pakistani intelligence service and the Mumbai attacks. The official, who spoke on the condition of anonymity, stressed that the investigation is ongoing.

Indian security agencies consider Deccan Mujahedeen a front for Lashkar-e-Taiba, Times Now reported, without saying where it got the information.

U.S. Secretary of State Condoleezza Rice, who visited Islamabad yesterday, pressed Pakistan to act against people suspected of involvement in the Mumbai assault. The government in Islamabad has received sufficient evidence to take action against suspects, she said.

“Pakistan has always been and still is the victim of terrorism,” President Asif Ali Zardari said at a press conference today in Istanbul, where he was holding talks with the presidents of Afghanistan and Turkey. “Pakistan is currently doing its own investigation and is waiting for concrete proof to be handed over before investigating the matter.”

The Bush administration wants to ensure the attacks don’t damage the more than five-year-old peace process between Pakistan and India, which have fought three wars since 1947, two over Kashmir.

Captured Gunman

Indian authorities say at least 10 gunmen targeted Mumbai’s main railway station, two five-star hotel complexes, a Jewish center and a hospital and that one survivor is in custody.

Several gunmen may have survived the three-day siege, Reuters reported, citing former CIA counterterrorism analyst Farhana Ali, who said sources in Pakistan told her at least 23 people took part in the assault.

The captured gunman, Ajmal Amir Kasab, 21, told interrogators he was sent by Lashkar-e-Taiba and identified the plot’s masterminds, the Associated Press reported, citing two Indian government officials it didn’t identify.

Kasab told police that Zaki-ur-Rehman Lakhvi, the group’s head of operations, recruited him, AP reported. The gunmen called another senior Lashkar leader, Yusuf Muzammil, on a satellite phone after hijacking an Indian vessel en route to Mumbai, according to the report.

A suspected collaborator in the attacks, Indian national Faheem Ansari, was arrested in February in northern India, carrying sketches of the hotels, the train terminal and other Mumbai sites attacked last week, Vikram Singh, director general of the Uttar Pradesh state police, said in televised comments.

To contact the reporters on this story: Vipin V. Nair in Mumbai at vnair12@bloomberg.net; Pratik Parija in New Delhi at pparija@bloomberg.net.

Last Updated: December 5, 2008 12:12 EST