The the diplomatic cables released by WikiLeaks described that a man pretending to be India's then External Affairs Minister, Pranab Mukherjee, called Pakistan President Asif Zardari to warn about a military attack in return to the terrorist attack on the country that killed 166 people.
Immediately after getting the phone call, Asif Zardari met Pakistan's military leadership and ordered its air force to be on high alert to counter India's possible attack. Also, Pak President asked other nations to pressurize India to withdraw its 'threat' on his country.
Acting to Asif Zardari's plea, the then US secretary of state, Condoleezza Rice, telephoned the Indian External Affairs minister and asked asked about the 'threat' he made to Pakistan. But, Pranab Mukherjee said that he had not called Pakistan President and was unaware about the phone call.
Mean while, when the American officials in New Delhi contacted with India's Ministry of External Affairs (MEA), a prominent Indian official mistakenly confirmed about country's External Affairs Minister's call to Pakistan.
The misunderstanding was cleared after three days when India's Joint Secretary (Americas) Gaitri Kumar confirmed that there had been no call from Pranab Mukherjee and it was the hoax call that made the confusion between both countries.
In a cable dispatched on Dec 4 2008, the US ambassador said he "suspects she incorrectly inferred that a Mukherjee-Zardari call took place from the fact that Mukherjee's office had, as a precaution, prepared points for him to use if Zardari were to phone [Indian] Prime Minister [Manmohan] Singh when he was unavailable, leaving Mukherjee to receive the call."