Cambodian Senate approves the agreement with the U.S. on the bilateral agreements on the non-extradition of U.S. citizens to the International Criminal Court (ICC).
Last week Cambodian National Assembly approved the measure.
Fifty senators who were present Monday morning, unanimously approved the agreement which means Cambodia and the US have agreed not to send each other's citizens to the ICC.
The US believes American citizens should be returned to the U.S. to stand trial for war crimes, and crimes against humanity as the U.S., does, can and will prosecute.
The US said it is fully responsible for its own citizens who are accused of these crimes abroad.
The bill will be sent to King Sihamoni to be signed into law.
Secretary of state of the ministry of foreign affairs Long Visalo said Cambodia became a member of the ICC on January 7, 2002.
Long Visalo said Cambodia signed the agreement with the US on the non-extradition of U.S. citizens to the ICC on June 27, 2003 and that so far 99 countries have signed this agreement with the U.S.