[caption id="attachment_103729" align="alignleft" width="300"] In this combination of three file photos shows, Taiwan's President Tsai Ing-wen, left, speaking at a ceremony in Asuncion, Paraguay, US President-elect Donald Trump, center, talking with President Barack Obama at White House in Washington and China's President Xi Jinping arriving at La Moneda presidential palace in Santiago, Chile. — AP [/caption] BEIJING/WASHINGTON — US President-elect Trump is clear about China's position on the Taiwan issue and China has maintained contacts with his team, the foreign ministry said on Monday, as Trump took to Twitter to complain about Chinese economic and military policy. Trump's unusual call with Taiwan President Tsai Ing-wen on Friday prompted a diplomatic protest on Saturday, though US Vice President-elect Mike Pence played down the telephone conversation, saying it was a "courtesy" call, not intended to show a shift in US policy on China. In Beijing, foreign ministry spokesman Lu Kang would not say directly who China had lodged "stern representations" with about Trump's call, repeating a weekend statement that it had gone to the "relevant side" in the United States. "The whole world knows about the Chinese government's position on the Taiwan issue. I think President-elect Trump and his team are also clear," Lu told a daily news briefing. "The Chinese side in Beijing and Washington lodged solemn representations with the relevant side in the US. The world is very clear on China's solemn position. The US side, including President-elect Trump's team, is very clear about China's solemn position on this issue." Pressed on who the diplomatic protest was lodged with, Lu said: "I think it's easy to understand ‘the relevant side'." "In fact, China has maintained contacts and communication with the team of President-elect Trump," he added, repeating a previous assertion, though did not give details. Lu also said he would not speculate on what prompted the call, but described the matter of Taiwan as the most important and sensitive question between China and the United States. Trump, who vowed during his campaign to label China a currency manipulator, issued more tough rhetoric on Sunday. "Did China ask us if it was OK to devalue their currency (making it hard for our companies to compete), heavily tax our products going into their country (the US doesn't tax them) or to build a massive military complex in the middle of the South China Sea? I don't think so!" Trump said on Twitter. China, Taiwan, the Philippines, Vietnam, Malaysia and Brunei claim parts or all of the energy-rich South China Sea, through which trillions of dollars in trade passes annually. Lu would not be drawn on directly commenting on Trump's tweets, but defended the China-US relationship. "The China-US economic and trade relationship has over many years always been a highly mutually beneficial one, otherwise it couldn't have developed the way it has today," he said. "China and the United States maintaining good relations, a steadily developing relationship, accords with the joint interests of both peoples." The diplomatic contretemps was one of several recently for the Republican president-elect, a real estate magnate who has never held public office and has no foreign affairs or military experience. Trump, who takes office on Jan. 20, is still considering his choice for secretary of state.