Accusing aid agency Save the Children of 'spying', Pakistan has asked it to leave the country within 15 days, in continuation of a crackdown on NGOs that commenced last December.
On Thursday, the police sealed the agency's Islamabad office, according to Reuters.
The charity, which has been operating in Pakistan for over 35 years, has denied the allegations.
Save the Children has been under the scanner by Pakistani authorities ever since the CIA-led operations conducted in 2011 that killed Al Qaeda terrorist Osama bin Laden, who was holed up in Abottabad, Pakistan.
Authorities in Pakistan were particularly miffed after Shakil Afridi, a Pakistani doctor, told Pakistani authorities that he was recruited by the CIA for assisting in finding Osama bin Laden through an official at Save the Children, according to the New York Times.
The charity's denials about its links to the doctor and the CIA notwithstanding, Islamabad has expelled 1,000 of its local officials.
A senior Pakistani police official told Reuters that investigation agencies in the country monitoring the charity officials' telephone calls and activities have found "their activities are very suspicious."
The official, who did not want to be named, added that Save the Children was involved in "anti-Pakistani projects."
Denying the allegations, Save the Children, in a statement, said, "We strongly object to this action and are raising our serious concerns at the highest levels."
"All our work is designed and delivered in close collaboration with the government ministries across the country and aims to strengthen public service delivery systems in health, nutrition, education and child welfare."
A copy of the closure order issued by Pakistan's Economic Affairs dated 11 June and published by The Express Tribune stated, "The competent authority has been pleased to decide that M/s Save the Children International be asked to windup its offices/operations in Pakistan forthwith and also issue direction to its expatriates to leave Pakistan within 15 days positively, under intimation to this Ministry."
As part of a nationwide crackdown since December last year, the Pakistan government has deregistered 3,000 local aid groups, according to CIVICUS, a global alliance of civil society organisations.