Bernie Sanders headlining 'don't take our health care' rallies in three states The events are aimed at pressuring GOP senators to oppose the bill.

 -- Sen. Bernie Sanders is headlining a "don't take our health care" rally tonight in Pittsburgh as a first stop on a three-state tour to mobilize opposition to the Senate health care bill, which the Vermont senator has called "by far the most harmful piece of legislation I have seen in my lifetime."

Sanders teamed up with progressive advocacy organization MoveOn.org to hold rallies this weekend in Pittsburgh; Columbus, Ohio; and Charleston, West Virginia, with the goal of pressuring Republican senators in each of the states to oppose the legislation released Thursday.

Republican Sens. Pat Toomey in Pennsylvania, Rob Portman in Ohio and Shelley Moore Capito in West Virginia have said they’re reviewing the legislation and have not made a final decision.

Toomey issued the most supportive statement of the three, calling the Senate bill, “an important and constructive first step in repealing Obamacare and replacing it.”

Five GOP senators have so far announced their opposition to the bill drafted by some of their Republican colleagues. Republicans can afford only two defections from the 52 senators in their ranks to pass the bill.

The nonpartisan Congressional Budget Office is expected to release its assessment of the bill early next week.

Sanders has slammed the legislation as "disastrous," saying in a statement Thursday that it "has nothing to do with health care. It has everything to do with an enormous transfer of wealth from working people to the richest Americans."

Sanders spokesperson Josh Miller-Lewis told ABC News, “We’re at a pivotal moment in the fight to save health care and the goal this weekend is to elevate that fight.”

All three of the states where the senator and MoveOn are holding rallies were won by President Trump in the 2016 election.

The first rally is tonight at 7 p.m. in Pittsburgh, followed by events Sunday in Ohio and West Virginia.