(CNN) The United States is suspending security assistance to Pakistan over what it sees as a failure by the Pakistani government to adequately clamp down on terror groups within its borders, the State Department announced Thursday.

"We will not be delivering military equipment or transfer security related funds to Pakistan unless it is required by law," State Department spokeswoman Heather Nauert told reporters.

The assistance being suspended is expected to top $1 billion. One administration official said the suspension includes around $1 billion in security assistance including foreign military financing (FMF) from prior years as well as $255 FMF financing from the 2016 fiscal year, which had not yet been disbursed and which the administration previously announced it would be withholding, as well as coalition support funds.

Historically, the United States has provided Pakistan over $1 billion in security assistance annually.

The Trump and Obama administrations had previously withheld $350 million in FY2016 coalition support funds due to similar concerns about Pakistan's failure to go after Taliban and Haqqani fighters.

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