The U.S. Senate early Wednesday morning has approved the most sweeping tax bill since the 1970s.
The Republican bill passed with by a 51-48 vote as announced by U.S. Vice President Mike Pence who chaired the vote.
The House of Representatives will vote for final approval on Wednesday, where it is expected to pass.
U.S. President Donald Trump is expected to sign the bill into law this week.
"The United States Senate just passed the biggest in history Tax Cut and Reform Bill," Trump said on Twitter after the vote.
Democrat Sen. Kamala Harris from California described the passed bill as "a travesty".
Harris wrote on Twitter that the law "gives even more tax breaks to the top 1 percent and permanently cuts corporate tax rates at the expense of middle class families. This isn’t what Americans wanted [...]."
Kirsten Gillibrand, senator from New York, called on the American people to channel their "anger and energy into defeating those who voted to put their donors before hardworking middle-class families".
The U.S. lawmakers in the House and Senate voted along party lines on Tuesday and early Wednesday. Republican Sen. John McCain of Arizona was absent because he is struggling with brain cancer.
After a series of amendments in a marathon session -- some changes had been scribbled in the bill’s margins -- it passed the House by a 227-203 vote on Tuesday, marking the largest tax overhaul in 31 years with nearly $1.5 trillion in cuts.
The bill aims permanently lower the corporate tax rate to 21 percent from the existing 35 percent.
The bill also reduces the number of tax brackets from seven to four at 12 percent, 25 percent, 35 percent and 39.6 percent.
President Donald Trump and Republican lawmakers claim the bill would serve as a boon to the middle class, despite several independent analyses that found it skewed toward corporations and the wealthy.