Rep. Peter King is urging the U.S. government to intervene in the case of a New York City police officer who has been detained in India for a month for possessing bullets in his luggage.

Mr. King, a Republican who represents Long Island, wrote in a letter to Secretary of State John Kerry that he believes the officer's arrest is payback for the arrest and strip search of an Indian diplomat in New York in December.

Manuel Encarnacion, a 49-year-old NYPD officer, was arrested on March 11 in New Delhi's Indira Gandhi International Airport after authorities checking his luggage found three bullets in the pocket of a jacket, New York City police officials said.

Mr. Encarnacion, a 10-year NYPD veteran who works in the 25th Precinct in East Harlem, had traveled to India for a vacation with his wife. He remains free on bail but cannot leave the country until his case is decided, the police officials said.

"We are staying very engaged with that issue in India," said New York City Police Commissioner William Bratton. "We are certainly concerned for that officer and his wife who is there with him."