Media playback is unsupported on your device Media caption What's in the Republican healthcare bill?

Republicans' long-awaited plan to replace former US President Barack Obama's health law is facing opposition from members of their own party.

House committees plan to begin voting on the legislation - which would repeal penalties for those who do not buy health insurance - on Wednesday.

But congressional Republicans have been saying the plan goes too far or does not go far enough.

Senator Rand Paul said the bill will be "dead on arrival" at the Senate.

He and other conservative critics have dismissed it as "Obamacare 2.0" or "Obamacare Lite".

The Affordable Care Act, known as Obamacare, helped 20 million previously uninsured Americans get health insurance.

However, increases in insurance premiums - which were also a problem before the health law - have irked many Americans.

Is Obamacare more popular than ever?

Can Obamacare be repealed?

Media playback is unsupported on your device Media caption Residents of Kentucky, one of the unhealthiest states in America, talk to the BBC about their hopes and concerns about Obamacare

What is the Republican plan?

The proposal unveiled on Monday would preserve some popular elements of the existing law:

allowing young people to remain on their parents' insurance plans until the age of 26

ban on insurers denying coverage to those with pre-existing conditions

But the plan is expected to cover fewer people than those who gained insurance under the Affordable Care Act. We will not know the exact numbers - or the cost - for about another week.

While penalties for those who don't buy health insurance would be scrapped, those who let their coverage lapse could see their insurance premiums raised by 30%.

The Republican legislation would limit future federal funding for Medicaid, which covers low-income people.

Nearly half of the Americans who gained healthcare coverage under Obamacare received it through the expansion of Medicaid, which would end in 2020 under the new plan.

The proposal would also eliminate subsidies for those with modest incomes, replacing them with age-based tax credits to mitigate the cost of premiums.

It also repeals the mandate that larger employers must offer insurance to their employees.

Image copyright AP Image caption Senator Rand Paul tweeted: "This sure looks like Obamacare Lite!"

What are Republican critics saying?

Republican leaders are trying to win over the party to what President Donald Trump described as "our wonderful new healthcare bill".

But four Republican senators have already said the plan does not adequately protect low-income people who received Medicaid coverage under the Affordable Care Act.

Three other, conservative Republican senators including Senator Paul have suggested the plan does not go far enough in abolishing Obamacare.

Members of the House Freedom Caucus, a group of about 30 hardliners, have also sounded sceptical.

House Oversight Committee chairman Jason Chaffetz has been savaged on social media for saying Americans need to choose between a new smartphone and medical insurance.

He told CNN: "And so maybe, rather than getting that new iPhone that they just love and they want to spend hundreds of dollars on, maybe they should invest in their own healthcare."

Mr Chaffetz later went on Fox News to walk back his comments, saying: "Maybe I didn't say it as smoothly as I possibly could."

Image copyright Twitter

Image copyright Twitter

Here comes the tricky part - Analysis by Anthony Zurcher, BBC Washington

Congressional Republicans are in a bind. They've spent the last seven years promising to tear up Obamacare "root and branch", in Senate Majority Leader Mitch McConnell's words, but demolition is only half the job.

They've got to find a replacement that satisfies hardliners who want a sharp break from the Democratic-supported status quo, moderates worried about taking away existing benefits from their constituents, fiscal hawks fearful of blowing a hole in the budget and - perhaps most importantly - President Donald Trump, who campaigned on preserving entitlements and improving coverage and care.

Right now, the House Republican leadership has a draft bill that seems to make no one happy. If Democrats stay united in their opposition, it won't take many Republican defections to sink the whole deal.

Republicans know they have to do something about healthcare. Lack of action could spark another conservative grass-roots revolt in 2018, endangering officeholders who worry more about primary challenges than general elections.

There are those who would be happy blowing up the government-managed healthcare system and worrying about the pieces later.

For the majority of Republicans, however, destruction is not a solution, it's a start. And what comes next is proving to be the tricky part.

Can the new plan pass Congress?

The Republican party has control of the both chambers of Congress and the White House.

But they must tread carefully because the Affordable Care Act is popular in many states, including some governed by Republicans.

If the Republican plan loses any more than 20 members of their own caucus in the House it is unlikely to pass.

The Senate leadership can only afford to lose the support of two Republicans if they are to succeed in dismantling Obamacare by a simple majority.

No Democrat on Capitol Hill is expected to vote for the new plan. Members of Mr Obama's party say the new legislation would leave many people uninsured.