Brazilian President Luiz Inacio Lula da Silva said Saturday that US military action in Venezuela would spark a “humanitarian catastrophe,” as he opened a summit of the South American Mercosur bloc.Lula’s comments come amid spiraling tensions between Washington and Caracas - and after US President Donald Trump left open the possibility of war against the government of Venezuelan strongman Nicolas Maduro.The US military has beefed up its presence in the Caribbean in recent months and carried out airstrikes against alleged drug boats in the region and in the Pacific, claiming that it is combatting narcotics trafficking.But Maduro says the campaign is part of a wider effort to carry out regime change in Caracas.For all the latest headlines, follow our Google News channel online or via the app.“Four decades after the Falklands war, the South American continent is once again haunted by the military presence” of a foreign power, Lula said in the southern city of Foz do Iguacu, referring to