India's navy is preparing for a terror attack by placing its warships on high alert following an attempt last month by al-Qaida’s South Asia wing to hijack a Pakistani navy frigate, The Indian Express reported Friday, citing military sources. The newly created group reportedly attempted to seize the Pakistani naval ship to fire rockets at U.S. vessels in the Arabian Sea.

Indian naval commanders have been ordered to watch for any unusual movements by Pakistani warships operating in the Indian Ocean, sources told The Indian Express. They also reportedly said that commanders have been asked to guard against strikes involving boats equipped with explosives.

“The Navy has repeatedly rehearsed for terror attacks on the high seas since 26/11… but the prospect that a Pakistani warship might go rogue and stage a sudden attack is a new order of threat altogether,” Commodore C Uday Bhaskar, a naval analyst said, according to The Indian Express. He was referring to the attacks of Nov. 26, 2008, on various high-profile targets in the city of Mumbai, including a Jewish synagogue.

Earlier this month, a dossier released online showed al-Qaida claiming that the attack on the Karachi naval facility on Sept. 6 by one of their two assault teams was intended to capture PNS Aslat, a Chinese-made F-22 frigate inducted into the Pakistani navy last year.

The group reportedly said that its plan was to “steer it towards Indian waters in order to attack Indian warships with anti-ship missiles.” The dossier also reportedly stated that the second assault team was in charge of seizing the PNS Zulfikar, another F-22 frigate, which they planned to use in an attack on a U.S. Navy vessel.

“Mujahid brothers present on board PNS Zulfiqar were to target and destroy the American oil tanker with the 72 mm anti-aircraft guns on their frigate,” the dossier stated, according to The Indian Express. “Meanwhile, other brothers on PNS Zulfiqar would target the American frigate protecting USS Supply using four anti-ship guided missiles.”

At least 10 militants were reportedly killed in the attack, which lasted for several hours, while about 17 navy personnel were reportedly detained by investigators due to their alleged involvement in the attack at a naval dockyard in Karachi.

“These mujahideen had taken control of the Pakistani ship, and they were advancing towards the American fleet when the Pakistani army stopped them," Search for International Terrorist Entities, or SITE, a monitoring service, quoted its spokesman, Usama Mahmoud, as saying, according to Reuters.

The dossier also stated that some attackers “who attained martyrdom during this operation were serving officers of the Pakistan Navy,” The Indian Express reported.

The Pakistani Taliban, which is closely associated with al-Qaida, had said that the attack was carried out with the help of insiders, Reuters reported earlier.

Meanwhile, a senior official reportedly said that it would be a challenge to guard against attacks in the Indian Ocean because of the large number of small ships operating in the waters.

“It’s often impossible to tell whether a fishing boat is part of the Indian fleet or not… and we have to balance the possible risks to our warships with the costs of opening fire on fishermen who mean no harm,” the senior official said, according to The Indian Express.