The Trump administration will suspend most security assistance to Pakistan, the State Department said on Thursday, expanding its retribution over militant safe havens that U.S. officials blame for ongoing violence in Afghanistan.

State Department spokeswoman Heather Nauert, speaking to reporters, said the suspension would allow the administration, which will freeze the aid payments but not allocate the money elsewhere, to reassess in the coming year.

Because the administration had previously said it would suspend $255 million in foreign military funding for Pakistan, the new announcement will have limited practical effect in the short term, as officials wait to see if Pakistan takes new action against militants.

But it sends as a strong signal to an on-again, off-again counterterrorism ally. The Trump administration is seeking to take a harder line against Pakistan as it expands military operations in Afghanistan, more than 16 years after that conflict began.

For years, U.S. officials have complained that Pakistan has allowed the Taliban and other extremists to operate within its borders. Taliban leaders are widely believed to reside in Pakistan, helping to direct insurgent operations in neighboring Afghanistan.

Pakistan denies those allegations and says the United States has failed to acknowledge the efforts it has taken against militant groups.

Also on Thursday, the State Department announced it would put Pakistan on a "watch list" for countries that fail to protect religious freedom.