BEIJING - China swung back to trade surplus in March from February's deficit of $31.48 billion, posting a $670-million trade surplus in the first quarter, the General Administration of Customs (GAC) said Tuesday.

The country's foreign trade in March rose 7.1 percent year-on-year to reach $325.97 billion, with a trade surplus of $5.35 billion.

Exports amounted to $165.66 billion in March, up 8.9 percent year-on-year, while imports reached $160.31 billion, the GAC data showed.

For the first quarter, China's imports and exports expanded 7.3 percent from a year ago to reach $859.37 billion, with its foreign trade with major trading partners growing in single-digits, according to the GAC.

Despite the lingering debt crisis, the European Union remained China's largest trading partner in the first quarter, but China-EU bilateral trade growth slowed to 2.6 percent year-on-year to reach $126.87 billion.

In the first three months, China's trade with the United States -- its second-largest trade partner -- increased 9.3 percent year-on-year to $106.77 billion, according to the customs data.

The 10-member Association of Southeast Asian Nations (ASEAN) held its position as China's third-largest trade partner, with China-ASEAN bilateral trade amounting to $86.78 billion, up 9.2 percent year-on-year.

Japan, which is still struggling to recover from last year's devastating tsunami and massive earthquake, posted a year-on-year decline of 1.6 percent in bilateral trade with China in the first quarter, or $79.44 billion.

However, China's trade with Russia, which joined the World Trade Organization this year, showed a rapid growth of 33 percent year-on-year to hit $21.49 billion.

Meanwhile, China's trade with Brazil, a major exporter of iron ore and other raw materials, gained 11.5 percent from the previous year to hit $18 billion in the first quarter.

During the January-March period of 2011, China reported its first quarterly trade deficit in seven years.