HANOI (Reuters) -France and Vietnam signed a deal on Monday for 20 Airbus planes, among other pacts, as President Emmanuel Macron visited Hanoi seeking to boost France's influence in its former colony, grappling with threats of crippling U.S. tariffs.

Macron's first formal visit to Vietnam, the first by a French president in nearly a decade, follows U.S. President Donald Trump's threats on Friday of 50% duties on EU goods from June that sharply fuelled tension with the 27-nation bloc.

Export-dependent Vietnam, under pressure from Washington to buy more American goods, has made pledges in trade talks to avert 46% tariffs that could impair its growth, fanning European concerns about deals at the region's expense.

"I am coming here to strengthen our ties in key areas - defence, innovation, the energy transition, and cultural exchanges," Macron wrote on X after his arrival on Sunday.

Deals signed covered the plane purchase, cooperation on nuclear energy, railways, Airbus earth-observation satellites and Sanofi vaccines, a list of documents seen by Reuters showed, confirming an earlier report.

France ruled the Southeast Asian country for about 70 years until it was forced out in 1954 after a major defeat at Dien Bien Phu in northern Vietnam. Ties have improved in recent decades, being upgraded last year to Vietnam's highest level.

On his trip, the first leg of a Southeast Asian tour that includes Indonesia and Singapore, Macron will visit a university in Hanoi on Tuesday, before flying to Jakarta, the Indonesian capital.

AIRBUS

The deal with European planemaker Airbus for Vietnam's low-cost airline VietJet to buy 20 A330neo wide-body aircraft follows last year's agreement for 20 of the jets.

The signing followed urging by European officials in recent weeks for Vietnam to be careful in concessions made to the White House, two officials based in Vietnam with knowledge of the discussions had told Reuters, referring to concerns on Airbus.

Airbus is the main supplier of jets to Vietnam, contributing 86% of its fleet, data from aviation analytics firm Cirium shows.

With an economy heavily dependent on U.S. exports, Vietnam has signalled the possible purchase of at least 250 Boeing planes by flag carrier Vietnam Airlines and rival VietJet.

Officials of both nations have said such deals would help cut its huge trade surplus with the United States and possibly appease Trump.

In talks with the United States, "Vietnam should make sure not to make decisions at the expense of European interests," one of the EU officials said.

Vietnamese leaders have been advised such steps could jeopardise close ties with the EU, which has a free trade deal with Vietnam and is a major buyer of its goods, they added.

(Reporting by Francesco Guarascio; Additional reporting by Tim Hepher, Lisa Barrington, Elizabeth Pineau and Sudip Kar-Gupta; Editing by Christian Schmollinger and Clarence Fernandez)