"The first quarter growth extended strong momentum in the second half of last year, and with the normally low basis of first quarter GDP, this year's first-quarter growth posted a strong pace," Nguyen Bich Lam, head of Vietnam's General Statistics Office (GSO), told reporters.

The Southeast Asian nation in 2017 recorded its quickest expansion since 2010, growing 6.81 percent thanks to record exports earnings and the government's economic reforms.

The data released on Thursday showed the processing and manufacturing industry grew 13.56 percent in the first quarter, boosted by output of manufacturing firms like Samsung, which produces most of its phones in Vietnam.

The country exported an estimated $12.3 billion worth of phones and spare parts in the first quarter, jumping 58.8 percent from last year. Trade surplus in January-March reached $1.3 billion.

Agriculture, seafood and forestry also posted strong growth in January-March, rising 4.05 percent from the same period last year. This is the first time in 13 years these sectors have posted growth of more than 4 percent, boosted by activity in rice and poultry, said Duong Manh Hung, head of GSO's national accounts system department.

Vietnam is the world's third largest exporter of rice and the second top producer of coffee. Rice exports in the first quarter of 2018 from Vietnam were forecast to rise 9.1 percent from a year ago to 1.35 million tonnes, brining in $668 million of revenue, a 23.8 percent annual increase.

January-March average annual inflation was 2.82 percent, the GSO said. Inflation this year could surpass the 4 percent limit set by the government if prices of some oil, some food products and pork spiked later this year, GSO's Lam said.

Vietnam targets 2018 annual growth at 6.7 percent, which Lam said is still a challenge despite strong growth in the first quarter as the exports-driven Vietnamese economy becomes increasingly exposed to international market conditions.

"The 6.7 percent target is not simple; it's still a challenge that requires comprehensive efforts from all authorities and enterprises," Lam said.