WASHINGTON - The US House of Representatives narrowly approved a bill to repeal Obamacare on Thursday, handing Republican President Donald Trump a victory that could prove short-lived as the healthcare legislation heads into a likely tough battle in the Senate.

The vote to repeal former President Barack Obama's signature domestic achievement, which enabled 20 million more Americans to get health insurance, was Trump's biggest legislative win since he took office in January, putting him on a path to fulfilling one of his key campaign promises as well as a seven-year quest by Republican lawmakers.

US President Donald Trump celebrates with Vice President Mike Pence and other Republicans after the House voted to pass their health-care bill, repealing Obamacare. Credit:Andrew Harrer

With the 217-213 vote, Republicans obtained just enough support to push the legislation through the House, sending it to the Senate for consideration. No Democrats voted for the bill.

The legislation is by no means a sure thing in the Senate, where the Republicans hold 52 of the 100 seats, and where only a few Republican defections could sink it.