Greece has reached an agreement with its foreign lenders on an austerity plan.

Greek Prime Minister Antonis Samaras said Tuesday, local time, that his country concluded negotiations on an austerity plan with the European Union, the European Central Bank and the International Monetary Fund.

However, parliamentary voting on the belt-tightening plan has been delayed by a week due to internal resistance. The socialist Pasok party and the Democratic Left party, which are members of the current three-party coalition government, are opposing the austerity plan. Greece's main opposition leftist party, Syriza, is vowing to block the passage of the austerity plan, which will be put to a vote in parliament next week.

Major labor unions are threatening to stage a general strike in protest against the austerity plan.