The US Senate passed a controversial “fast-track” trade bill in a 62-37 vote on Friday. It is a key part of President Barack Obama's pivot to Asia, which aims to counter China's rising economic and diplomatic power via the Trans-Pacific Partnership (TPP).

The bill will now head to the House of Representatives for a vote early next month, where it is expected to face a tougher showdown.

If passed by the House, the fast-track bill will give Obama the power to negotiate trade pacts with other countries and submit them to Congress without lawmakers being able to introduce amendments to them.

But some House Democrats have expressed worry about the bill's impact on jobs and the environment, while some conservatives oppose giving the White House more power.

Senate votes 62-37 to pass trade fast track bill. A hard-fought win for Pres Obama. But prospects in the House even more difficult. — Mark Knoller (@markknoller) May 23, 2015

The Senate ended debate on the bill on Thursday in a 62-38 vote, pushing it to the forefront of Friday's agenda. Obama called that vote "a big step forward.”

In a close 51-48 vote Friday, senators rejected an amendment that would’ve mandated any future trade bills to feature penalties against countries that manipulate the value of their currency in order to sell products overseas at lower prices.

The chamber also rejected an amendment by Sen. Elizabeth Warren (D-Mass.) that would have prevented approval of the TPP if it included an Investor-State Dispute Settlement system, which gives multinational corporations the ability to fight regulations in other countries. Liberals have railed against the ISDS, arguing that it would allow companies to undermine US laws.

Meanwhile, another amendment that would’ve required Congress to approve of any additional country that wants to join the TPP in the future.

READ MORE: Show us the deal: Senators Warren, Manchin demand Obama disclose TPP

The main aim of fast-track, which would initially have a three-year term, is to implement the Trans-Pacific Partnership – a trade deal that would link 40 percent of the world's economy.

Along with the United States, 11 other countries have taken part in TPP negotiations: Australia, Brunei, Canada, Chile, Japan, Malaysia, Mexico, New Zealand, Peru, Singapore, and Vietnam. The deal would exclude China and serve to counter its growing economic and diplomatic influence in the Asia-Pacific region.

The proposed partnership has been a source of intense debate in Washington and throughout the United States – and Obama's Democrats are divided on the matter.

Those in favor of the partnership include big businesses, Congressional Republicans, and President Obama himself.

“TPP is good for American businesses and American workers...we will make the case on the merits as to why it will open up markets for American goods, American exports, and create American jobs,” Obama said in a statement on April 28.

But those against TPP – including labor unions and the Tea Party – say the deal would put American manufacturing jobs at risk.