The U.S. trade deficit widened to $51.8 billion in March, up from a revised February figure of $45.4 billion, the U.S. Department of Commerce reported Thursday.

The trade deficit widened at the fasted rate in 10 months, led by imports of non-petroleum goods. It was also the highest trade gap registered for that month. Economists, who predicted a downward revision to the country's economic growth in the first quarter, expected the deficit to wide to $50 billion, according to a Thomson Reuters survey.

Year-to-date, the trade deficit is nearly $600 billion, or 7 percent more than the previous year.

The deficit is an indicator of national productivity. A widening trade gap indicates a slower economy as consumers buy more imports than producers bring in selling goods made in the country.

March's US trade figures open the door to a sharp downward revision to annualized first-quarter GDP growth, perhaps to just 1.2 percentfrom 2.2 percent, said Paul Dales, senior economist at Capital Economics. Only a small part of the rise was due to the higher oil price boosting oil imports. Instead, the bulk was due to the non-petroleum deficit widening, to $23.3 billion from $17.8 billion.

The 14 percent jump in the trade gap was the largest since the 16 percent in May 2011.

Most of those non-petroleum products came from China. The U.S. trade deficit with the Asian giant increased to $21.7 billion in March, up from $19.4 billion the previous month. The record trade gap with China in 2011 was just over $295 billion.

U.S. imports increased to a record $238.6 billion, or 5.2 percent. Exports rose nearly 3 percent to $186.8 billion. The ongoing euro zone debt crisis raises the question of whether the U.S. can sustain its momentum in exports.  

Weak growth both here and abroad is inconsistent with the robust increases reported on both sides of the trade ledger in March, Joshua Shapiro, chief U.S. economist at MFR Inc. in New York told The Associated Press.