WASHINGTON (REUTERS) - US President Donald Trump on Sunday (Feb 24) raised hopes that the United States and China would settle their trade dispute ahead of a March 1 deadline as negotiators met to wrap up the latest round of talks.

The US president said in a tweet that the trade talks on Saturday were "very productive". Talks were extended through the weekend in a bid to iron out differences on changes to China's treatment of state-owned enterprises, subsidies, forced technology transfers and cyber theft.

The two sides have had no agreement on an enforcement mechanism. Washington wanted a strong mechanism to ensure that Chinese reform commitments were followed through to completion, while Beijing insisted upon what it called a "fair and objective" process.

On Sunday, top officials including US Treasury Secretary Steven Mnuchin and Chinese Vice-Premier Liu He arrived for talks at the Winder Building, which houses the headquarters of the United States Trade Representative, an hour later than usual.

Both Mnuchin and Liu went inside without commenting, with Liu smiling when asked if the two sides would have a deal by the end of the day.

Trump said on Friday there was a "good chance" a deal would emerge, and that he might extend the March 1 deadline and move forward with a meeting with Chinese President Xi Jinping.

Extending the deadline would mean putting on hold a scheduled increase in tariffs to 25 per cent from 10 per cent on US$200 billion (S$270 billion) worth of Chinese imports into the United States.

An extension would hold off a worsening of the trade war that has already disrupted commerce worth hundreds of billions of dollars of goods, slowed global economic growth and roiled financial markets.

On Friday, Trump and Mnuchin said US and Chinese officials had reached an agreement on currency issues, but did not give details. US officials have long argued that China's yuan is undervalued, giving it a trade advantage and partly offsetting US tariffs.

China has committed to buying an additional 10 million metric tonnes of US soybeans. Reuters reported exclusively on Wednesday that both sides were drafting memorandums of understanding (MOUs) on cyber theft, intellectual property rights, services, agriculture and non-tariff barriers to trade, including subsidies.

But Trump said he did not like MOUs because they are short-term, and he wanted a long-term deal. Trump said the biggest decisions could be reached when he meets with Xi, probably in Florida next month, and that their talks may extend beyond trade to encompass Chinese telecommunications companies Huawei Technologies and ZTE Corp.