HANGZHOU, China, Sept 4 (Reuters) – Prime Minister Theresa May said on Sunday she wanted her security advisers to review a delayed nuclear power investment from China – a source of diplomatic tension – as she arrived in the country to attend a G20 summit.

May upset Chinese officials in July by delaying a $24 billion project that would see French firm EDF build Britain’s first new nuclear power plant in decades with the help of $8 billion from China.

Speaking during her first visit to China, May was asked whether she would ask the National Security Council, a team of ministers supported by intelligence officers, to look at the potential security implications of the Hinkley deal.

“I will be doing exactly as you’ve said,” May replied, saying it would be part of her decision-making process. The comment marked the first official acknowledgement that national security was a factor in her decision.

The initial delay caught investors by surprise and has cast doubt over whether May, who took office in July following Britain’s vote to leave the European Union, will continue to court China as a major source of infrastructure investment.

“This is the way I operate,” May earlier told reporters en route to the summit, which will include a one-to-one with Chinese President Xi Jinping.

“I look at the evidence, …take the advice and consider that and come to my decision.”

A final decision is expected later this month.

May, a former interior minister, is wary of the risks of allowing China to invest in nuclear projects, according to a former cabinet colleague. The EDF deal is viewed as a precursor to Chinese involvement in another two nuclear plants.

Asked whether she trusted China, May said: “Of course we have a relationship with them… What I want to do is build on that relationship.”

She also stressed a need to broaden the group of nations that Britain can trade with and tap for cash to help reinvigorate its power, transport and technology infrastructure.

“This is the G20, this is about talking to a number of world leaders. I’m going to give the message that Britain is very much open for business… I want to be talking about the opportunities for free trade around the world.”

(By William James. Editing by Sandra Maler and John Stonestreet)