The US Pacific Command has banned its troops in the Philippines from bars and nightclubs with the trial under way of a US Marine accused of murdering a transgender Filipina he met in a bar.
Thousands of US and Filipino soldiers will begin ten days of military exercises on Monday
Spokesman for the US forces Captain Alex Lim said there will be strict controls on the free time of US troops.
"There is a 10pm curfew. The restrictions include no bars and clubs," he said.
He also said that US soldiers will only be allowed to eat meals "in the vicinity of their place of dwelling," for example at their hotel.
Cpt Lim would not say why the restrictions were imposed but conceded they came after a US serviceman was arrested for the murder of a transgender Filipina he met in a bar last October after taking part in military exercises in the Philippines.
US Marine Private First Class Joseph Scott Pemberton is now on trial in the Philippine city of Olongapo.
Activist groups have seized on the incident to attack the defence alliance between the US and the Philippines, staging frequent street protests against the presence of US forces.