The U.S. Pacific Command has banned its troops in the Philippines from bars and nightclubs, a spokesman said Saturday, with the trial underway of a U.S. Marine accused of killing a transgender Filipina he met in a bar.

Thousands of American and Filipino soldiers were set to kick off 10 days of annual joint military exercises Monday, according to Capt. Alex Lim, a spokesman for the U.S. forces.

But there will be strict controls on their free time.

"There is a 10 p.m. curfew. The restrictions include no bars and clubs," he told Agence France-Presse.

He also said that American soldiers will only be allowed to eat meals "in the vicinity of their place of dwelling.”

Lim would not say why the restrictions were imposed, but conceded they came after an American soldier was arrested over the alleged murder of a transgender Filipina he met in a bar in October after taking part in military exercises in the Philippines.

U.S. Marine Pfc. Joseph Scott Pemberton is now being tried for the crime in the Philippine city of Olongapo. Jennifer Laude, whose former name was Jeffrey, was found dead in a motel room there on Oct. 11. She had apparently been drowned in a toilet bowl.

Activist groups have seized on the incident to attack the defense alliance between the United States and its former colony, staging frequent street protests against the presence of U.S. forces.

However, the Philippines, which has one of the weakest militaries in the region and which has a seething territorial dispute with China over parts of the South China Sea, has been seeking greater defense support from the U.S. in recent months.

Al Jazeera and Agence France-Presse