Donald Trump told his predecessor Jimmy Carter that he was concerned about China becoming a superpower, the former US president has disclosed. Trump made his first call as president to Carter from the West Wing in April, according to the White House. On Sunday, Carter, who established formal diplomatic relations with China as president in 1979, told a Sunday school in his native Georgia about their conversation. “The main thing that he emphasised to me was, the main purpose of his call, was to say very frankly to me on a private line that the Chinese were getting way ahead of the United States,” he said. Carter said Trump had called him in response to a letter he had sent about relations with China, adding that he was “delighted” and “surprised” to receive the call. The 94-year-old had marked the 40th anniversary of the re-establishment of diplomatic relations between Washington and Beijing with a warning of the risks of sliding into a “modern cold war”. “As you have heard to your concern perhaps, the Chinese are likely to be number one superpower economically within the next few years,” Carter told the congregation at Maranatha Baptist Church in his hometown of Plains on Sunday. He then questioned what being a superpower meant, saying it’s “not just who has the most powerful military, but who is a champion of the finer things in life”. Markets are focused on the wrong trade war risk As a devout Christian who frequently teaches Sunday school classes, Carter said peace, the environment, human rights and equality were things all Christians should believe in. The White House said in an earlier statement that Carter sent Trump “a beautiful letter” about the negotiations with China and they had “a very good telephone conversation about President Trump’s stance on trade with China and numerous other topics”. Carter, the longest living former US president, was making his first public appearance since he had hip replacement surgery last month after a fall. In April he suggested that the different amounts America and China spent on their militaries might have had an impact on their respective levels of economic growth. He said the United States was “the most warlike nation in the history of the world” due to a desire to impose American values on other countries, whereas China was investing its resources into infrastructure projects such as high-speed rail. “Since 1979, do you know how many times China has been at war with anybody? None. And we have stayed at war,” he said.