The Pakistani government ordered the Islamabad bureau chief for the New York Times to leave the country right before the start of the country's historic parliamentary elections, the newspaper said on its website.
Declan Walsh, 39, was told early Thursday morning that his visa was being canceled and had to leave the country within 72 hours, "in view of your undesirable activities," the newspaper said.
Pakistan's Interior Ministry did not offer any further details in explaining the expulsion order, which Walsh said was delivered to his home at 12:30 a.m. by police officers in the form of a two-sentence letter.
"It is informed that your visa is hereby canceled in view of your undesirable activities," the order stated. "You are therefore advised to leave the country within 72 hours."
The Times said it has "strongly protested the move and is seeking his reinstatement."
The timing of the order precluded Walsh from personally observing the first election in the country's history where one elected civilian government completes its term and hands over power to another elected government.
Walsh is a longtime correspondent who has lived and worked in Pakistan for nine years, most of it for The Guardian newspaper of Britain.
The Times indicates it hired Walsh in January 2012 and since then he has written extensively about the country's issues, including its often violent political convulsions, activities of Islamist insurgencies and strained relations relations with the United States, which has been conducting drone attacks in Pakistan's border areas with Afghanistan.
Jill Abramson, the Times' executive editor, expressed concern about the expulsion order in a letter of protest addressed to Pakistan's interior minister, Malik Muhammad Habib Khan. She described Walsh as a "reporter of integrity who has at all times offered balanced, nuanced and factual reporting on Pakistan."
The accusation of undesirable activities, she wrote, "is vague and unsupported, and Mr. Walsh has received no further explanation of any alleged wrongdoing."
As well, the order's timing was also surprising, she said, considering Pakistan is holding national elections that are widely regarded as an important democratic milestone.
"The expulsion of an established journalist, on the day of the voting, contradicts that impression," she wrote.
Pakistani officials have not responded to repeated requests for more information submitted of the past two days.
The ramp-up to the elections has been notably violent, with suicide bombings and other attacks by militants adversely affecting the ability of several political parties to campaign.
On Thursday, unidentified gunmen kidnapped one of the candidate, is a son of former Prime Minister Yousaf Raza Gilani, throwing the election into more turmoil.
Walsh said the circumstances of the expulsion order's delivery were highly unusual. He had been on a social visit Thursday evening, he said, when he received a phone call from an unrecognized number advising him to "come home now."
So, when he arrived, Walsh saw half a dozen police officers and a plainclothes officer waiting outside. The plainclothes officer handed him the letter and asked him to sign for it.
"I opened the letter in front of him because I knew it was something serious," he said. "This was a complete bolt from the blue. I had no inclination that anything of this sort was coming."
Free-press advocates expressed anger at the news of Walsh's departure, saying that it reinforced Pakistan's reputation as one of the most inhospitable countries for journalists.
Pakistani journalists are frequently intimidated, assaulted and sometimes subjected to even worse, according to Reporters Without Borders, an advocacy group based in Paris.
The country has also become the deadliest country for journalists since the start of 2013, with six killed in connection with their work.
The Committee to Protect Journalists said Pakistani authorities have not prosecuted a single suspect in the 23 murders of journalists over the last decade.