Pakistan is "hypnotically obsessed" with India's military and has done "damn near nothing" to prosecute suspects in the 2008 terrorist attack on Mumbai, top Indian diplomats have told US officials.
They also repeated their claims that the Pakistani army was involved in the Mumbai siege.
The comments, made known through leaked US documents published on Friday, contain few major revelations about the overall relations between the two nuclear-armed rivals.
But the decidedly undiplomatic language used in private conversations provide a colorful perspective to India's frustrations with Pakistan.
Foreign Secretary Nirupama Rao said earlier this year that peace talks, which have been on hold since the 2008 siege, could not move ahead until Islamabad did more to dismantle the Pakistan-based terrorist infrastructure that New Delhi says supports militants.
The talks "can't just be switched on," Rao told US Sen John Kerry during a February visit to New Delhi, insisting Islamabad had not yet done enough to prove it was serious about terrorism.
The comments were conveyed in cables sent by the US Embassy in New Delhi to the State Department and obtained by WikiLeaks.
They were posted Friday on the website of the British newspaper The Guardian.
Speaking to Kerry just before he flew to Islamabad for meetings with top Pakistani officials, Rao also predicted the senator would be told there that India's military doctrine was a continuing threat.
The Pakistani military is "hypnotically obsessed" with India's military, Rao said according to the cable, which was marked "confidential."
The US has repeatedly urged the two rivals to improve their ties.
Better relations between India and Pakistan would help Washington in its war in Afghanistan, because it would allow Islamabad to shift troops away from the Indian border and toward its western frontier to fight militants there.
Pakistan and India have fought three wars since 1947, two over conflicting claims surrounding the Himalayan region of Kashmir, which is divided between them but claimed in its entirety by both.
India accuses Pakistan's intelligence agencies of supporting militants who carry out attacks in India, including those in Mumbai.
Pakistan wants to resume the peace talks, but India says Islamabad has not done enough to punish the perpetrators of the Mumbai siege or ensure there will not be a repeat.
A few rounds of preliminary talks have ended with little except public recriminations or platitudes about the need for peace.
Shortly before the Kerry meeting, home minister Palaniappan Chidambaram told visiting FBI director Robert Mueller that Pakistan had "done damn near nothing" to prosecute the Mumbai suspects, according a cable.
While Pakistan has arrested seven people in connection with the attacks, and top officials insist it is bringing those behind militant attacks to justice, those trials have not yet properly begun.
The United States has to delicately balance its relations with the two nations. It cannot upset India, a growing economic and democratic giant, and must also strengthen ties with Pakistan, which it needs to stabilize Afghanistan.
Pakistani officials could not immediately be reached for comment.
In 2009, meanwhile, then-foreign secretary Shivshankar Menon told then-assistant secretary of state Richard Boucher: "Let's not insult one another by telling a story that the Pakistan Army was not involved" in the Mumbai attacks.
The cable quoted Menon as saying that the Pakistani army paid wages to members of Lashkar-e-Taiba, the Pakistan-based Islamist militant group believed to be behind the siege.
"They're either unwilling to take action, or incapable, or both; any way you look at it, they're involved."
Pakistan's powerful army and spy agencies - which operate largely out of the control of the civilian government - have for years treated militants who attack India as allies.
In early 2009, Menon warned the US ambassador that Pakistan's military was gaining ground in Islamabad at the expense of civilian leaders.
"The good guys are losing," Menon said.