Image copyright Reuters Image caption US Trade Representative Robert Lighthizer told Congress he was pursuing a trade deal that would protect US firms' intellectual property

Congress has warned the Trump administration that any trade deal with China should secure substantive policy changes.

The statements come as trade negotiations enter a critical period.

US President Donald Trump recently said he may meet Chinese President Xi Jinping to announce a deal next month.

There is growing concern in Congress that he will fail to resolve underlying disagreements over intellectual property and unfair trading practices.

At a House Ways and Means Committee hearing on Tuesday, both Republican and Democrat lawmakers urged the Trump administration's top negotiator Robert Lighthizer to continue to take a tough approach.

"This administration has chosen to take a path of high-risk confrontation," said Rep Richard Neal, a Democrat who represents Massachusetts.

"It must hold out for a good deal."

Mounting tariffs

Mr Trump initiated the trade war in 2017 citing unfair trading practices, including accusations that Chinese companies were stealing intellectual property from American firms by forcing them to transfer technology to China.

The US has imposed tariffs on $250bn worth of Chinese goods, and China has retaliated by putting duties on $110bn of US products.

Mr Trump has also threatened further tariffs on an additional $267bn worth of Chinese products, which would see virtually all Chinese imports into the US become subject to duties.

The trade dispute has prompted concern over global economic growth and is putting additional pressure on China's economy, already showing signs of strain.

In the US, it has unnerved financial markets, hurt farmers and raised costs for American companies, increasing the political pressure on the president to deliver an agreement

On Wednesday, members of Congress expressed concern about the administration's decision to impose tariffs. But they said they agreed with the Mr Trump's stated goals and urged the administration to resist the temptation to strike an easy deal.

"We can all strongly agree that China has cheated on trade for decades," said Rep Kevin Brady, a Republican who represents Texas.

"While we want China to buy more US goods ... it's even more important for us to hold China accountable."

Warm welcome

Previous congressional hearings on Trump's trade policies have been tense as lawmakers criticise the administration's tariffs and fights with Europe, Canada and other allies.

However, this time US Trade Representative Robert Lighthizer, who has a reputation as a hard-liner on US-China issues, received a warm welcome.

Image copyright Reuters Image caption China's vice premier Liu He (l) met President Trump and chief trade representative Robert Lighthizer in February

Mr Lighthizer said that he was focused on securing a deal that can be enforced and removes pressure on US companies to share technology with China.

"I don't think we should accept anything that doesn't have structural changes and is not enforceable," he said.

"Real progress" was being made in the negotiations, he added.

Mr Lighthizer said an agreement could include provisions for regular meetings between officials from the two countries.

He also brushed aside speculation that his relationship with the president was under strain. The president recently publicly contradicted Mr Lighthizer over what form a final agreement should take.