The Government must act to resolve a trade dispute which could threaten thousands of jobs, a leading union boss has said.
Unite assistant general secretary Tony Burke said workers at Bombardier, which employs around 5,000 people in Northern Ireland, are "holding their breath" over the company's future.
A preliminary finding is due later on Tuesday from the US authorities after aerospace giant Boeing claimed its multinational rivals Bombardier received unfair state subsidies from the UK and Canada, allowing them to sell airliners at below cost prices in the US.
Speaking at the Labour Party conference in Brighton, Mr Burke told delegates: "We call upon the British and Canadian governments to meet with Boeing to resolve this crisis.
"Workers in Belfast are holding their breath.
"The Prime Minister and the Government need to make it clear to (US President Donald) Trump they will not stand back and watch our members' jobs and our communities threatened like this.
"Mrs (Theresa) May needs to stand up for our members in the aerospace industry and for decent jobs and for manufacturing in the U.K."
Mr Burke was moving an emergency motion on the company at the event, and a vote on whether to debate the motion will be taken on Tuesday afternoon.
He added: "Of course Boeing is emboldened by Trump's America First policy and as a result thousands of skilled workers' futures are in doubt.
"What is needed is to end this corporate bullying by Boeing, putting these good jobs at risk.
"The UK Government is the second largest purchaser of Boeing products including P8 marine surveillance aircraft and Apache helicopters estimated to be around £4 billion worth of work."