* Trump seeks to reduce U.S. trade deficit with Thailand
* Thai foreign minister hails 'special' meeting of leaders
* Thailand is Washington's oldest ally in the Southeast Asia (Adds comment from Thai deputy PM)
WASHINGTON/BANGKOK, Oct 3 (Reuters) - President Donald Trump wants to reduce the U.S. trade deficit with Thailand, he told the country's prime minister on Monday in a meeting that marked another sign of warming ties between Washington and Bangkok.
Trump, who has sought to improve U.S. trade ties with a variety of countries since taking office in January, put Thailand in the spotlight when he sat down with Thai Prime Minister Prayuth Chan-ocha in the Oval Office.
"Our relationship on trade is becoming more important and it's a great country to trade with," Trump told the Thai official before reporters. "I think we're going to try to sell a little bit more to you, if that's possible."
The U.S. Trade Representative's office reported that the U.S. trade deficit with Thailand was $18.9 billion last year, the 11th largest faced by the United States.
The meeting was a sign of improved ties between the United States and Thailand after the relationship cooled when the Thai military took power in a 2014 coup.
Human rights groups had strongly opposed the meeting, seeing it as a reward for an authoritarian leader who has cracked down on opposition and rolled back democratic freedoms.
Thai Foreign Minister Don Pramudwinai hailed the meeting between the leaders as "special".
"It shows special attention for the Thai prime minister," Don told official Thai media traveling with the delegation.
Don used the visit as an opportunity to praise his government's achievements. "If we weren't good, they probably wouldn't invite us," he said.
The junta has promised to hold a general election in 2018 but has yet to set a firm date.
Prayuth raised the issue again on Monday.
"I told him (Trump) ... next year we will announce a general election date," Prayuth told reporters.
The Obama administration was deeply critical of the Thai junta and refused to extend an invitation to Prayuth to the White House.
Human Rights Watch in a statement given to Reuters in Bangkok called on members of the U.S. Congress to demand that the Trump administration pressure Thailand to restore democracy and called on the Pentagon to "cool their engagement" with Thai leaders.
"They should be demanding that the Trump administration not give the junta a free pass," John Sifton, Human Rights Watch's Asia Advocacy director in Washington, told Reuters.
"They should publicly reaffirm that U.S. law bars direct military assistance to Thailand and outline key benchmarks Thailand needs to meet to restore the bilateral relationship to its prior condition."
Secretary of State Rex Tillerson visited Bangkok in August in what was the highest level visit to Thailand by a U.S. official since the coup.
Prayuth and members of his cabinet will also meet with representatives of Thai businesses in the United States during the three-day visit.
Thailand is often cited as the oldest U.S. ally in Southeast Asia and Washington has been urging the region to do more to cut funding streams to North Korea over its nuclear programme.
Prior to the 2014 coup, Thailand agreed to buy four Black Hawk helicopters from the United States.
But Thai deputy prime minister Prawit Wongsuwan said on Tuesday that the leaders did not discuss the sale of U.S. defence equipment.
"They haven't allowed us to buy weapons from them for a while now," Prawit told reporters.
(Reporting By Steve Holland and Yara Bayoumy IN WASHINGTON; Additional reporting by Amy Sawitta Lefevre, Aukkarapon Niyomyat and Pracha Hariraksapitak in BANGKOK; Editing by Chizu Nomiyama, David Gregorio and Michael Perry)