“The president of the United States has supported our efforts. In fact we will be meeting with the president on Tuesday,” McCain said during a visit to Mexico.

He did not say how many senators would attend the meeting.

McCain told reporters after meeting with Mexican President Enrique Pena Nieto that many details must be worked out between Obama and senators trying to produce legislation.

Asked about the prospects for reaching a deal, he said: “I am guardedly optimistic that we could by the end of the next month. There’s still a number of agreements that need to be made before I can assure you that we will have a resolution.”