(Adds White House reaction, para 6)
By Jessica Donati and Hamid Shalizi
KABUL, Aug 20 (Reuters) - Afghanistan has given a New York Times reporter 24 hours to leave the country, accusing him of not cooperating with an investigation into his reporting, the Attorney General's office said on Wednesday.
Matthew Rosenberg, 40, was summoned for questioning on Tuesday after the newspaper ran a story about officials discussing plans to form an interim government and "seize power" if a deadlock over the presidential election failed to break soon.
"Due to the lack of proper accountability and non-cooperation, the Attorney General's office has decided that Matthew Rosenberg should leave Afghanistan within 24 hours," the office said in a statement. "He will not be permitted to enter the country again."
Rosenberg said he and his newspaper had been cooperating fully.
"We simply requested a lawyer as is our right under Afghan law," he said. "We were also never informed of a formal investigation and we do not understand how insisting on the right to a lawyer is not cooperating."
Caitlin Hayden, spokeswoman for the White House National Security Council, said the Afghan government's move was a "significant step backward for the freedom of the press in Afghanistan and should be reversed immediately".
Afghanistan is in the midst of a ballot that has dragged on for months, with both candidates claiming victory after the June 14 run-off and allegations of mass fraud threatening to derail the process.
AFGHANISTAN CITES SECURITY RISK
"They had brought us there under the guise of a kind of semi-informal chat," Rosenberg said of the talks. "It was kind of polite but insistent that we give them the names of our sources."
Attorney General's office spokesman Basir Azizi said Rosenberg was being investigated for publishing a story about government officials conspiring to "seize power" without disclosing the identity of his sources.
"The report is against our national security because right now, the election problem is ongoing and talks are at a very intricate stage," Azizi told Reuters by phone.
The United Nations is supervising an audit of all eight million votes cast, but the process has proceeded slowly as rival camps scrutinize each vote.
At the same time, members of a joint commission appointed by deadlocked candidates Abdullah Abdullah and Ashraf Ghani are meeting to hammer out an agreement on a unity government.
The framework deal was brokered by U.S. Secretary of State John Kerry, who has twice flown to Kabul since the run off, but little progress in fleshing out the structure of the government has been made since his departure two weeks ago.
NAI, a group supporting a free press in Afghanistan, said the expulsion order violated laws protecting freedom of expression by the media.
"We think rather than it being a legal matter, it's a political game," said Abdul Mujeeb Khalvatgar, the head of NAI.
"There are people in the government of Afghanistan trying to somehow keep the international community out of the picture of the elections in Afghanistan." (Writing by Jessica Donati; Editing by Jeremy Laurence)