By Phuong Nguyen

HANOI, April 4 (Reuters) - Vietnamese budget airline VietJet is set to sign a $200 million aircraft finance deal with a partner of investment fund KKR at a meeting in Washington next week attended by planemaker Boeing, according to an internal schedule seen by Reuters.

The programme, signed by VietJet head and dated March 31, was sent in a letter to the Vietnamese government. The Southeast Asian nation is scrambling to avoid crippling U.S. tariffs announced by the Trump administration on Wednesday to reduce Vietnam's large trade surplus with Washington.

VietJet executives would sign the financial agreement with AV Air Finance Company, a partner of KKR KKR.N, at the Vietnamese embassy in Washington on April 9 with the participation of Vietnam's Deputy Prime Minister Ho Duc Phoc, according to the schedule.

The financing deal is to support the purchase of aircraft, according to the document. At the same event VietJet executives will meet Boeing BA.N representatives to discuss cooperation and "affirm commitment to expanding strategic relations," the document said.

It is not clear whether the financing deal, if confirmed, is meant to support a possible new order, or whether it would allow the airline to place a deposit for existing purchasing deals.

VietJet has agreed to buy 200 Boeing 737 MAX jets in a deal first signed in 2016 and revised afterwards, but no jet has yet been delivered.

VietJet is also considering ordering 20 Boeing 787 jets, according to a person with direct knowledge of the discussions.

The company said in a statement in January that it had agreements worth nearly $50 billion with leading U.S. corporations, including Boeing, and was negotiating additional agreements worth approximately $14 billion.

It also said Boeing will deliver this year the first 14 of the 200 aircraft VietJet has already ordered.

The company did not elaborate on that announcement when asked.

VietJet, KKR, its partner and Vietnam's foreign affairs ministry did not reply to requests for comments about the financing deal.

Boeing deferred to VietJet for comments.

Another two industry sources said both VietJet and flag carrier Vietnam Airlines HVN.HM were in talks to buy more passenger jets, without elaborating on the possible seller.

Vietnam Airlines did not reply to a request for comment.

Multiple Vietnamese and U.S. officials had said the purchase of planes by Vietnamese companies could be a way for the country to address trade concerns from the Trump administration.

Vietnam has publicly bemoaned the U.S. 46% tariffs on Vietnam-made goods that are set to take effect on April 9, unless the country obtains a reprieve from Washington.

Deputy Prime Minister Phoc is set to travel to the U.S. from April 6, according to the government portal, which did not announce any meetings with U.S. officials.

Hanoi has announced over the last weeks multiple concessions to avoid U.S. tariffs, including the cut of import duties and a pledge to buy more U.S. goods.

(Reporting by Phuong Nguyen in Hanoi; additional reporting by Tim Hepher in Paris; writing by Francesco Guarascio;Editing by Elaine Hardcastle)

((Francesco.Guarascio@thomsonreuters.com;))