Activists in Islamabad protest Sunday against the opening of the U.S.Embassy in Jerusalem, as relations between Pakistan and the United States continue to deteriorate. (Farooq Naeem/AFP/Getty Images)

Just over one month ago, Col. Joseph E. Hall, a military attache at the U.S. Embassy here, was involved in a car crash in the capital that took the life of a 22-year-old man driving a motorcycle and seriously injured a passenger riding on the back. 

On Saturday, following weeks of diplomatic and legal wrangling over Hall’s diplomatic immunity, Pakistani officials prevented him from boarding an American military plane and leaving the country, according to Pakistani diplomats and media reports.

The incident at a military airfield near the capital, which was followed breathlessly on live TV here, was the latest dramatic twist in a bilateral dispute that has raised anti-American sentiment among Pakistanis and reflects the hardening relationship between two long-term security allies that are increasingly at odds on major issues.

The C-130 cargo plane from Bagram air base in Afghanistan landed here in the morning, and Hall was reportedly driven to the airfield to board it. But after Pakistani security officials there realized who he was, he was not granted permission to leave, according to these reports. The plane returned to Bagram, and Hall returned to the embassy. 

Embassy officials declined to comment Sunday, citing the “sensitivity” of the situation. There was also no comment from the State Department in Washington. Pakistan has formally asked U.S. officials to withdraw Hall’s diplomatic immunity, but the matter is being reviewed by Pakistani courts, and there has been no official resolution.

The airfield incident occurred one day after the U.S. and Pakistani governments formally imposed mutual curbs on the travel and movements of each other’s diplomats. The reciprocal tightening of restrictions had been expected for some time, and it was not officially related to the Hall case, but it seemed yet another indication of the serious decline in bilateral relations, especially over U.S. accusations that Pakistan harbors Islamist insurgents.

The new American restrictions limit all Pakistani diplomats and their families to traveling no more than 25 miles from Washington or other cities with Pakistani consulates without prior permission. One State Department official said last month that the U.S. limits were being applied in response to prior similar restrictions by Pakistan, but some Pakistani officials called them offensive and unwarranted.

Pakistani analysts expressed concern that the lingering dispute over Hall’s diplomatic immunity will also further inflame public anti-American sentiment here. On April 7, Hall was initially reported to have run a red light and hit a motorcycle driven by Ateeq Baig, 22, who died of his injuries. The passenger on the bike was also wounded. 

Video footage of the traffic intersection, recorded by closed-circuit cameras on time-stamped film and widely circulated since then, showed a large white vehicle passing through two red lights and continuing as a motorbike crossed into its path. The vehicle hit the bike head on, and the riders were flung into the air.

Hall, who was reportedly driving, was allowed to leave the scene and was never arrested, but Baig’s father pleaded with the courts to prosecute him. The Interior Ministry put Hall on a “black list” that temporarily denied him the right to leave Pakistan, and on Friday, the Islamabad high court ruled that he did not enjoy absolute immunity. The court gave the government two weeks to decide if he should be barred from leaving.

“If the American authorities want to resolve this issue, they should opt for negotiations. Instead, they have imposed restrictions on Pakistani diplomats. This is not a wise handling of the situation,” said Hasan Askari Rizvi, a defense and foreign policy analyst in Lahore. Especially with national elections approaching, he said, “I fear the relationship will get worse if serious efforts are not made to improve ties.”

While Pakistan has previously imposed some limits on the travel and activities of foreign diplomats, the new restrictions are far more extensive and suggest a particular concern about spying activities. They revoke a list of perks such as allowing diplomats to use tinted car window glass, nondiplomatic license plates, unregistered cellphone SIM cards and unapproved radio communications in their residences and safe houses.

There has been no suggestion that Hall, an air and defense attache who has not spoken publicly about the traffic accident or his diplomatic status, was engaged in any such activities. 

Nevertheless, both the incident and the subsequent legal and diplomatic fights bear some similarities to a far more controversial case from early 2011, in which Raymond A. Davis, a CIA contractor, shot and killed two Pakistani motorcyclists in Lahore, and a third man was hit and killed by a vehicle that came to assist Davis.

Pakistani officials tried to prosecute Davis for murder, but he was eventually allowed by the courts to leave the country and was flown to Afghanistan after paying several million dollars in blood money, a legally accepted form of compensation in Pakistan, to the victims’ families.