HANOI (Reuters) -Vietnam's imports from China and exports to the United States both reached a post-pandemic record in April, amid talks with Washington to reduce Hanoi's trade surplus and a crackdown on Chinese goods being shipped to the U.S. via its territory.

The Southeast Asian nation faces the risk of 46% duties on its exports to the U.S. if the White House confirms this rate at the end of a global tariff pause in July. This could undermine Vietnam's growth model and hit multinationals exporting from the country, including Samsung and Nike ( NKE ).

Hanoi has made multiple offers to the Trump administration to avoid high levies, including clamping down on illegal transshipment of Chinese goods to the U.S. via Vietnam. Goods benefit from lower tariffs if labelled as 'Made in Vietnam'.

However, trade trends that have attracted U.S. criticism are accelerating, potentially complicating Vietnam's efforts to extract U.S. concessions in ongoing trade talks.

The Trump administration wants to reduce trade imbalances, but Vietnam's surplus with the United States - already one of the highest globally - expanded by nearly 25% in the four months to April year on year, according to Vietnam's statistics agency.

In March alone, it exceeded $13.5 billion, the highest monthly figure ever, U.S. data showed.

Manufacturers in Vietnam are ramping up exports to the United States before a possible tariffs hike, multiple industry executives said.

In April, shipments to the U.S. exceeded $12 billion, 34% higher than a year earlier, and the largest value recorded after the COVID-19 pandemic, Vietnam's customs data showed.

Vietnam's Cai Mep deep-sea port, which handles most of the country's sea-borne exports to the United States, is experiencing a surge in shipments to the U.S., said Soren Pedersen, vice president at SSA Marine, which operates a port in Cai Mep and is one of the world's largest port operators.

He told Reuters Cai Mep, which hosts all major shipping companies, including Maersk, MSC and COSCO, has 26 container ships booked for weekly departures to the U.S. in May, "a record high" from an average of 20-22.

"Most container terminals are now operating at or near full capacity," he said, noting that was in anticipation of possible higher tariffs.

CHINA IMPORTS

At the same time, Vietnam is ramping up imports from China, which also reached a post-pandemic record in April, exceeding $15 billion, according to customs data.

Vietnam's exports to the U.S. in recent years have been fuelled by imports from China, with inflows from Beijing closely matching the value and swings of exports to Washington.

Vietnam's imports of Chinese goods, often components or raw materials used in Vietnamese factories, grew nearly 31% in April from a year earlier. Industrial production rose 8.9% in the same period.

White House officials have accused Vietnam of being a mere waypoint for goods made in China and shipped to the United States, with no or insufficient value added in the country to justify 'Made in Vietnam' labels.

In response, Hanoi started a crackdown on illegal transshipment in April, increasing controls on imported goods and the issuance of certificates about products' origins.