ISLAMABAD, Pakistan — Pakistan on Friday placed travel restrictions on United States diplomats based in the country, the latest in a series of retaliatory measures that threaten to plunge already strained relations to their worst level in years.
The restrictions in Pakistan were imposed on the same day that the United States barred diplomats working at the Pakistani Embassy in Washington from traveling outside of a 25-mile radius around the city without approval.
The United States has long complained that Pakistani police and security officials frequently harass American diplomats and their staff with traffic stops and citations that require considerable time and effort to resolve. Six weeks ago, the State Department threatened to impose a travel restriction on Pakistan’s Washington diplomatic corps if the harassment did not end by Friday.
On Friday, American officials imposed the restrictions.
In a letter from Pakistan’s Ministry of Foreign Affairs delivered to the American Embassy in Islamabad, Pakistani officials said that they had established a fast-track mechanism on April 27 to address American complaints about harassment but had yet to receive a single complaint through it.
While the State Department’s restrictions apply only to diplomats assigned to the embassy in Washington and their family members, Pakistan’s restrictions apply to all American diplomats stationed anywhere in Pakistan.
Pakistan imposed other restrictions as well, including banning tinted windows on embassy cars and the use of diplomatic plates on diplomats’ personal vehicles. Both sides said they would waive their respective restrictions on a case-by-case basis.
“We have received official notification of new restrictions placed on U.S. diplomats in Pakistan,” said Gregory McLean, a State Department spokesman.
Asked whether the United States would respond to Pakistan’s even tougher measures, Mr. McLean declined to say.
“We are in regular communication with our Pakistani counterparts,” he said. “We do not discuss details of diplomatic conversations.”
Security concerns have constrained some travel by American diplomats in Pakistan, but the new limits make it impossible for diplomats to leave some of the country’s major cities.
In January, the Trump administration announced that it had suspended nearly all of the $1.3 billion in annual security aid given to Pakistan, an announcement that came just three days after President Trump complained on Twitter that Pakistan had “given us nothing but lies & deceit” and accused it of providing “safe haven to the terrorists we hunt in Afghanistan.”
The Trump administration has also sought to strengthen ties with India, Pakistan’s bitter rival.
Shuja Nawaz of the Atlantic Council,