Pakistan says it has “reliable intelligence” India is planning a military attack this month, something India dismissed as “war hysteria”.
Foreign minister Shah Mehmood Qureshi made the comments on Sunday.
Already tense relations between the two deteriorated this year when Pakistan-based militants killed dozens of Indian troops in Indian-administered Kashmir.
India responded with air strikes on what it said was a militant training camp in Pakistani territory.
Soon afterwards, Pakistan shot down an Indian jet in Pakistan-administered Kashmir, and captured its pilot. He was handed back to India days later.
The aerial attacks in February across the Line of Control (LoC) dividing Indian and Pakistani territory in Kashmir were the first since a war in 1971.
Both nuclear-armed nations claim all of Muslim-majority Kashmir, but only control parts of it.
What has Pakistan said?
Tensions seemed to have eased after the clashes, but on Sunday the Pakistani foreign minister said his country had intelligence to suggest an imminent Indian attack.
“There are chances of another aggression against Pakistan and according to our information this action can take place between April 16 and 20,” Mr Qureshi told reporters.
The foreign minister said he made the allegations “with responsibility”, arguing the aggression aimed to raise “diplomatic pressure” against his country.
Pakistan has also summoned India’s deputy high commissioner to protest against what it says are India’s plans.
How did India respond?
Foreign officer spokesman Raveesh Kumar said Pakistan had “a clear objective of whipping up war hysteria in the region”.
“This public gimmick appears to be a call to Pakistan-based terrorists to undertake a terror attack in India,” the spokesman said.
He insisted that Pakistan “cannot absolve itself of responsibility” for the militant car bomb in Kashmir.
India has long accused Pakistan of giving safe haven to militants from the Jaish-e-Mohammad (JeM) group, which said it was behind the attack in Pulwama.
Pakistani Prime Minister Imran Khan has denied his country had any role in the bloodshed. He has offered to cooperate with an investigation if India could provide evidence of Pakistan’s involvement.
India is due to vote in general elections soon, and opponents of Prime Minister Narendra Modi allege he is using tensions with Pakistan to boost support for his party. Mr Modi’s BJP party has strongly denied the suggestion.
Pakistan detained dozens of suspected militants after the Kashmir attack, including relatives of Masood Azhar, the founder of JeM.
The allegations of an imminent Indian attack came on the same day Pakistan released the first batch of about 360 Indian prisoners.
The 100 people set free on Sunday are mostly fishermen who strayed into Pakistani waters.
Analysis: A battle fought on the airwaves
By Secunder Kermani, BBC Pakistan Correspondent
Since the beginning of the Pakistan-India crisis earlier this year, Pakistani officials have attempted to lay claim to the moral high ground: portraying Indian politicians as cynical warmongers, who pushed for military action against Pakistan in order to cash in on nationalist sentiment during India’s elections (due to start this week).
News of this alleged planned Indian attack comes as authorities in Delhi face increasing pressure from their own public – their claims to have shot down a Pakistani plane, and struck a militant training camp in Pakistan in February look increasingly dubious.
But the Pakistani Foreign Minister didn’t provide any evidence of these alleged Indian plans at his press conference, and the Pakistani Army has so far remained silent on the issue. The remarks also come ahead of the arrival in Islamabad of a number of senior international journalists, many based in India, who were last week invited to come and meet the Pakistani leadership.
The conflict between Pakistan and India is being fought on the airwaves as well as the battlefield, and separating facts from spin is not easy.