ISLAMABAD (Reuters) -- Nuclear-armed Pakistan put its forces on high alert after a hoax caller pretending to be India's foreign minister spoke to President Asif Ali Zardari in a threatening manner two days after the attacks on Mumbai began, "Dawn" newspaper has reported.
"It's true," a diplomat with knowledge of the November 28 phone exchanges told Reuters when asked whether the newspaper report was correct.
Throughout the next 24 hours, Pakistan's air force was put on "highest alert" as the military watched anxiously for any sign of Indian aggression.
"Dawn" reported that the caller, posing as Indian Foreign Minister Pranab Mukherjee, also tried to telephone U.S. Secretary of State Condoleeza Rice, but due to specific checks by U.S. officials the call was not put through.
The episode triggered intense international diplomacy, with some world leaders fearing that Indian and Pakistan could slip into an accidental war, the newspaper said, sourcing its report to unnamed diplomatic, political and security officials.
India has blamed Islamist militants based in Pakistan for the three-day rampage in the financial capital last week that killed 171 people.
There is an ongoing investigation by both sides to determine who made the call, and it remains unclear whether it was made from India or Pakistan, the newspaper said.
Pakistani officials said the caller ID was a Delhi number, but Indian officials have said the number could have been manipulated.