FILE PHOTO: Labourers work at a garment assembly line of Thanh Cong textile, garment, investment and trading company in Ho Chi Minh city, Vietnam July 9, 2019. Picture taken July 9, 2019. REUTERS/Yen Duong/File Photo/File Photo

By Khanh Vu and Phuong Nguyen

HANOI (Reuters) - Vietnam's economy grew 8.23% year-on-year in the third quarter, up from 7.96% in the second, despite a 20% U.S. tariff on exports that took effect on August 7, government data showed Monday.

Exports over the July-September period rose 18.4% from a year earlier to $128.57 billion, while imports jumped 20.2% to $119.66 billion, resulting in a trade surplus of $8.91 billion, the National Statistics Office said in a report.

As well as the 20% tariff, the United States also imposed a 40% levy on transshipments from third countries through Vietnam.

Total September exports fell 1.7% compared to a month earlier, amounting to a value of $42.67 billion. Shipments to the United States over the month were down 1.4% compared to August.

Two-way trade between Vietnam and the United States stood at $112.8 billion during the first nine months of this year as a whole, while trade with China reached $134.4 billion, the NSO said. China is Vietnam's largest source of imports.

Industrial production in the Southeast Asian manufacturing hub also rose 9.1% in the first nine months of this year from a year earlier, the NSO said.

Consumer prices in September rose 3.38% from a year earlier, it said, and retail sales were up 11.3%.

Foreign arrivals to the country in the first nine months of this year also rose 21.5% year on year to 15.4 million, it said.

Vietnam is targeting gross domestic product growth of 8.3%-8.5% this year. That is faster last year's 7.09% growth, and higher than the World Bank's forecast of 6.6% and the International Monetary Fund's estimate of 6.5% growth.

On Friday, the central bank said it would prioritise growth over the remainder of the year and it urged banks to cut their lending interest rates.

The central bank said credit growth, a key driver of the economy, was expected to increase 19%-20% this year.

For the first nine months of this year, exports rose 16% from a year earlier to $348.74 billion, while imports were up 18.8% at $331.92 billion, amounting to a trade surplus of $16.82 billion, according to the NSO.

The United Nations Development Programme has estimated that tariffs could cut Vietnam's exports to the U.S. by one-fifth, making it the worst-hit country in Southeast Asia.

(Reporting by Khanh Vu, Phuong Nguyen and Francesco Guarascio; Editing by David Stanway)