Prime Minister Theresa May, US President Donald Trump was on the phone about a threat to the jobs at Bombardier in Belfast of a trade dispute.
In 2016, the Canadian company Bombardier received an order for the delivery of up to 125 CSeries passenger jets to US airline Delta.
The wings for the CSeries aircraft are made at Bombardier’s Belfast plant.
However, rival aircraft company Boeing has authorities in the US that the deal was unfairly subsidized by the Canadian state.
The U.S. Department of Commerce is due to a decision later this month.
It Bombardier could duties hitting with a criminal.
What do Bombardier in Northern Ireland?
Turbulent times for Bombardier
The rates could make it very difficult for Bombardier to find new CSeries aircraft customers in the United States.
The CSeries project will support hundreds of jobs in Belfast.Call from Trump
A spokesman said the government is “working tirelessly for the protection of the Bombardier’s operations and their high-skilled workers in Belfast”.
“Ministers in the government have fast and intense, with Boeing, Bombardier, the U.S. and the Canadian government,” she said.
“Our priority is the promotion of Boeing is about to fall, his fall, and the search for a negotiated solution with Bombardier.”
The spokesman said Prime Minister Theresa May asked the question and protect your concern for the jobs, in Northern Ireland, in a call with a President Donald Trump last week.
She also said Business-Secretary of state Greg Clark went to Chicago to a meeting, Boeing chairman, president and chief executive officer, Dennis Muilenburg.
Bombardier management in Belfast are also understood to have recently informed the trade unions about the importance of the matter.
Boeing has claimed that Bombardier is engaged in ‘price-dumping’, with the agreement to sell 75 of its aircraft for almost $14m (Â£10.6 m) below their cost.
He also points out that the Delta deal came after the regional government in Quebec saved effectively, the CSeries program with a $1 billion investment.
He said: “equity infusions from the public coffers, not only saved the program but have Bombardier the resources it needs to aggressive the opponent the US market.”
Bombardier has described the allegations as “absurd” and said the government investment, “orders the observance of the laws and regulations in the law, in which we do business”.