Both warships are already scheduled to be there till November 6 for public viewing as part of Naval Day celebration, but have now reportedly been put on security alert.
According to police sources, central security agencies sent an e-mail cautioning them about a possible attack by Pakistan Navy-backed terrorists. The media further quoted the sources, as saying that security agencies had intercepted conversation about Indian and American naval assets in Kolkata being targetted, and therefore, had swung into action immediately.
The terror alert in Kolkata comes a couple of days fater the Pentagon told the United States Congress that Pakistan has been using militants as proxies to counter India's superior military might
The Pentagon claims in its latest six-monthly report on the current situation in Afghanistan that Pakistan is using such proxies to counter the Indian armed forces as well as to hedge against the losing of power and control in Afghanistan.
Such relationships oppose Pakistan's commitment to support Afghan-led reconciliation and these groups continue to act as the primary source of contention between Afghan- Pakistan bilateral relations, claims the Pentagon report.
The Pentagon also mentioned an attack on the Indian consulate in Herat that took place three days ahead of the swearing-in ceremony of Indian Prime Minister Narendra Modi.
The fact that Modi is believed to be close to Hindu nationalist groups may have played into the timing of the attack, said the Pentagon.
However, welcoming the Pentagon report, External Affairs Ministry spokesman Syed Akbaruddin said that if the international community is acknowledging the fact that terrorism derives support from Pakistan, it is something that New Delhi welcomes.
He said India is of the view that terrorists should not be segmented.