BIARRITZ, France – President Donald Trump said Monday he is optimistic that the U.S. will reach an agreement with Beijing to alleviate an ongoing trade war but offered few details to counter concerns that China is waiting until after the election to strike a deal.

"They want to make a deal," Trump told reporters at the end of the G-7 summit that took place over the weekend in this seaside town.

Trump's optimism came days after the leaders of both countries significantly ratcheted up trade tensions, including with a series of higher tariffs. Trump announced Friday that he would raise tariffs on $550 billion in Chinese goods, sending markets into a tailspin.

The president said that Chinese officials reached out twice to the administration late Sunday in an effort to restart talks. "We've got two calls, very very good calls, very productive calls," Trump told reporters. "They mean business."

A Chinese foreign ministry spokesperson said he was unaware of any such calls, and Trump declined to say which Chinese officials had called.

Instead, Trump pointed to a statement from Chinese Vice Premier Liu He that he hoped both countries could "calm" tensions. Trump said he agreed with that sentiment and dismissed a question about his tendency to criticize the Chinese government one day and praise them the next.

"Sorry it's the way I negotiate," Trump told reporters. "It's done very well for me over the years and it's doing even better for the country."

Trump made the remarks hours before markets opened in the U.S. Those markets plunged Friday after China raised retaliatory tariffs on $75 billion in American made products. Later Friday, Trump responded by raising tariffs on $550 billion in goods.

Trump said Friday he would raise from 25% to 30% U.S. tariffs on $250 billion in Chinese products and would increase from 10% to 15% new tariffs on a remaining $300 billion in goods – some of which are set to take effect next month.

The Dow Jones Industrial Average was up nearly 300 points Monday in midday trading.

Trump came under pressure from allies on trade during his G-7 visit. Early in the talks, new British Prime Minister Boris Johnson – who has sought to align himself with Trump on many issues – suggested all nations should focus on "dialing it down if we can.”

French President Emmanuel Macron, standing alongside Trump during the early moments of the press conference on Monday, said he was concerned that the trade tensions between Washington and Beijing had increased global economic instability.

“What’s bad for the world economy is uncertainty," Macron said. "The quicker an agreement is arrived at, the quicker the uncertainty will dissipate.”