PHNOM PENH (Reuters) - The United States has ended its programme with Cambodia to send students to top American military academies, a U.S. embassy official said on Thursday, marking the latest sign of strains in the relations between the two countries.

Washington has been concerned over China's growing military presence in Cambodia, with the Southeast Asian country becoming one of Beijing most important allies in the region.

The decision to end the programme had been made after Cambodia had ended some areas of military cooperation, U.S. Embassy spokesman Arend Zwartjes said.

"Following Cambodia's curtailment of cooperation in several areas of traditional bilateral military-military engagement, the country lost its eligibility for the U.S. military service academy program," Zwartjes told Voice of America (VoA).

Zwartjes said, however, Cambodian students currently enrolled in U.S. military academies would be permitted to complete their undergraduate programmes.

"The United States has encouraged the Government of Cambodia to assist its students with remaining tuition costs," Zwartjes said.

Some elite members of Cambodian society, including HM, the oldest son of Prime Minister HE, have in recent decades graduated from the prestigious U.S. Military Academy at West Point.

HM is now a deputy commander and joint chief of staff of the Royal Cambodian Armed Forces (RCAF).

Chhum Socheat, a spokesman at Cambodia's defence ministry, and government spokesman, Phay Siphan, did not immediately respond to requests for comment on the issue.

(Reporting by Prak Chan Thul; Editing by Ed Davies)