China's exports rose 8.3% in September from a year earlier, up from August's 4.4%, customs data showed on Monday, as stronger shipments to Southeast Asia and Europe offset weaker demand from the United States.

Imports grew 7.4%, bringing the monthly trade surplus to US$90.5 billion.

Exports to the ASEAN bloc climbed 14.7% in the first nine months of the year, while those to the European Union rose 8.2% and to the United States fell 16.9%.

Economists said the rebound reflected a low comparison base and more working days than a year earlier but warned growth may turn negative in the fourth quarter as global demand softens and higher U.S. tariffs weigh on trade.

They added that Beijing's new 500-billion-yuan (about US$70 billion) policy-based financing plan for infrastructure, announced in late September, could help support China's economy and partly offset weaker external demand.