Thai soldiers stand next to national flags as they participate in the opening ceremony for Cobra Gold at a military academy in Nakhon Nayok province, east of Bangkok, Feb 9, 2015. [Photo/Agencies]

BANGKOK - Thailand and the United States on Monday launched their annual Cobra Gold military exercise, a major multilateral training event scaled down this year amid mutual recriminations over last year's Thai military coup.

In a speech marking the opening of the exercise, W. Patrick Murphy, the top US diplomat in Thailand, said that bilateral relations since the May 22 coup had been challenging and reiterated that Washington hopes for a quick return to democracy. Thailand's military-led government has said it expects to hold elections early next year.

US officials previously announced that this year's exercise in eastern Thailand would be scaled down, cancelling a large-scale amphibious landing and emphasizing humanitarian operations training. More than 13,000 military personnel from seven nations are participating, and other nations are observing.

Senior US State Department official Daniel Russel drew criticism from coup supporters last month when he indicated Washington's displeasure over what it considers undemocratic rule by the generals. 

Russel "made clear our unwavering friendship and support for the Thai people, as well as our hopes for the country's return to democracy as soon as possible so we can restore our bilateral relationship to its full potential," Murphy said. "Still, we can't deny that this period is a challenging one for us all, and has necessitated a modified Cobra Gold exercise this year as Thailand manages its return to elected, civilian-led government."

He added though that the multination military training exercise transcends any bilateral relationship and strengthens cooperation in the region.