OTTAWA, Ontario — Some 155,000 federal workers, including 35,000 from Canada’s tax agency, went on strike after midnight Wednesday in what their union is calling one of the largest strikes in the country’s history.

The Public Service Alliance of Canada said the strike was called after talks with the government failed to produce an agreement.

The strike involving the Canada Revenue Agency comes as tax returns are due.

Chris Aylward, the union’s national president, said the bargaining teams would remain at the table throughout the strike.

The federal Treasury Board said it offered the union a 9% raise over three years. But the union has pushed for annual raises of 4.5% over the next three years.