President Donald Trump on Wednesday urged Republican senators to push through a last-ditch attempt to repeal the Affordable Care Act before the end of the month.

In a tweet, the president for the first time explicitly endorsed the health-care plan spearheaded by Sens. Lindsey Graham, R-S.C., and Bill Cassidy, R-La. The senators are rushing to pass the bill before a Sept. 30 deadline to use budget rules that would allow them to approve it with only Republican votes.

The health-care bill sets up a block grant system to allot money to the states. Many of them are expected to see less federal funding under the plan than they currently get.

"I hope Republican Senators will vote for Graham-Cassidy and fulfill their promise to Repeal & Replace ObamaCare. Money direct to the States!" Trump wrote on Twitter.

Trump: I hope Republican Senators will vote for Graham-Cassidy and fulfill their promise to Repeal & Replace ObamaCare. Money direct to States!

The senators backing it say it will give states more control over their health care rather than the federal government. It faces a tough fight and potentially razor-thin margin in the Senate.

Critics have expressed concerns that it will drastically increase the number of uninsured Americans and lead to fewer financial protections for people with pre-existing conditions. Ten bipartisan governors have urged the Senate not to pass the plan, while numerous major health-care groups have criticized the bill.