Republican U.S. Sen. Scott Brown and Democratic challenger Elizabeth Warren are back on the campaign trail as the hotly-contested race heads into the homestretch.

Brown is scheduled to visit to a senior center in Quincy, the last stop in what the campaign has called a "Keep the Promise" tour to discuss Medicare.

Brown says the new federal health care law would cut Medicare by $716 billion. But Warren and other Democrats say the cuts over the next decade are aimed at waste, fraud and insurance company subsidies and will not reduce any benefits to Medicare recipients.

Warren is scheduled to be joined on the campaign trail on Friday by Democratic Sen. Al Franken of Minnesota. The two will appear at a forum in Lexington to discuss clean energy and later attend rallies in Cambridge and Worcester.