U.S. Sens. Bernie Sanders and Elizabeth Warren are locked in a close race for the top spot in next month's Massachusetts presidential primary, while likely Bay State Democratic voters are also nearly evenly split on incumbent Sen. Ed Markey and his challenger, Rep. Joe Kennedy III, according to new poll results.

The poll of 450 likely Democratic primary voters, released Friday by UMass Lowell's Center for Public Opinion, found 20 percent support for Warren in her home state and 21 percent for Sanders.

Former South Bend, Indiana Mayor Pete Buttigieg polled in third place at 15 percent, former Vice President Joe Biden came in fourth with 14 percent, and former New York City Mayor Mike Bloomberg saw 12 percent support. No other candidate cleared 10 percent in the poll.

Massachusetts voters will begin casting ballots in the presidential primary during an early voting period next week and on the March 3 primary day. While only 4 percent of those polled were undecided, almost four in 10 said they could change their mind.

In the Senate race, Markey and Kennedy are also neck-and-neck with backing from 34 percent and 35 percent, respectively, of likely primary voters. Eight percent would cast their ballots for another candidate if the election, scheduled for Sept. 1, were held today, while 23 percent are undecided.

Support in the contest varied among subsets of likely Democratic primary voters polled. Kennedy fared better among men, those over 45 and self-identified moderate and conservative voters, while Markey saw better numbers with women, voters aged 18 to 44 and liberals.

The poll was conducted from Feb. 12 to Feb. 19 and has a margin of error of 6.1 percent.