ISLAMABAD (Reuters) - Pakistan has told at least 10 foreign-funded aid groups to close, an umbrella agency said on Wednesday, including a charity founded by hedge fund billionaire and philanthropist George Soros, the group said.

Pakistan has toughened its stance towards domestic and international non-governmental groups in recent years, accusing some of using their work as a cover for espionage.

In January, it ordered about a dozen groups working on women’s issues and human rights to halt their operations.

A representative of the Pakistan Humanitarian Forum (PHF), which represents 63 international aid groups, said the Ministry of Interior had issued 10 of its members “letters of rejection”, meaning their applications to register had been rejected.

The forum did not identify the 10 groups but two international groups, the Pakistani branch of the Soros’ charity the Open Society Foundations, and ActionAid, said they had been told they had to close.

“We obviously find what has happened both disappointing and surprising, and are urgently seeking clarification,” the executive director of the Open Society’s Pakistani office, Saba Khattak, said in a statement.

The group had spent $37 million on grants and relief assistance in Pakistan since 2005, she said.

The interior ministry did not respond to requests for comment.

However, the ministry, in a letter to one of the 10 groups and seen by Reuters, said its registration application had been denied.

“Wind up operations/activities of above said INGO within 60 days,” the ministry said in the letter.

It did give a reason why the group had to stop its work.

The ministry lists 139 international non-governmental organizations (INGO) on its website that have submitted registration applications, of which 72 are still being processed.

There is no list of those whose applications have been denied.

“During the lengthy INGO registration process we provided all the information and documents required and are confident we comply with all necessary rules and regulations,” ActionAid country director Iftikhar Nizami said in a statement.

This year, medical charity Medecins Sans Frontieres was ordered to stop work at three facilities in violence-plagued ethnic Pashtun areas bordering Afghanistan, although the interior ministry lists the group as an approved INGO.

The Save the Children aid group fell afoul of the government in 2011, when it was linked to a Pakistani doctor recruited by the CIA to help in the hunt that led to the killing of al Qaeda militant leader Osama bin Laden in the town of Abbottabad.

Save the Children’s foreign staff were expelled from Pakistan soon after the accusations surfaced, but more than 1,000 local staff continued to operate.

The charity denied any links with the doctor or the CIA.