China pledged Friday to boost cooperation with fellow BRICS countries in response to soaring frictions with the US, as it seeks to cultivate alliances to help it weather a bruising trade war.China will enhance coordination on macroeconomic policies with fellow BRICS members Brazil, Russia, India and South Africa in response to the "challenges posed by the changing policies of certain developed countries," said assistant foreign minister Zhang Jun.The comment was an oblique reference to US President Donald Trump's decision to plunge the US and China into a tit-for-tat trade war by imposing tariffs on billions of dollars worth of goods - and threatening to up the ante with $200 billion more.While the US has "no respect for rules of international law," the BRICS countries all shared a clear stance towards global markets, Zhang said, echoing Beijing's oft-stated position that China - which the US and others have accused of having a mercantile, protectionist trade policy - is a guardian of free trade."We all firmly support multilateralism and the multilateral trade regime," he said. "We all oppose unilateralism and trade protectionism."The comments come as Beijing has instructed companies to look for imports beyond the US, seeking closer trade ties in Europe and elsewhere to offset potential losses from American tariffs.President Xi Jinping will attend the 10th BRICS Summit in Johannesburg, South Africa from July 25 to 27.Meanwhile, Trump has picked fights with key US allies such as Canada, sparking fears of an all-out global trade war.