President Donald Trump dealt a double blow to Affordable Care Act on Thursday night, in a major step toward fulfilling his campaign promise to dismantle the Obama-era health care policy.

In a notice issued late night, the president scrapped vital federal subsidies underpinning Obamacare, withdrawing support of up to $7bn to insurance companies to help them cover the medical needs of low-income Americans.

An executive order by the president a few hours earlier had opened the door to cheaper and less comprehensive insurance, which experts predict will result in health plans for the sick becoming more expensive.

The executive order is aimed toward expanding choices and alternatives to Obamacare plans and increase competition to bring down costs for consumers, the White House press release stated.

In a speech before signing the executive order, Trump blamed Democrats who "broke the American healthcare system by forcing the Obamacare nightmare onto the American people." He promised that he would take care of high premiums, according to the White House website.

The order would allow consumers to buy short-term policies, which do not have to comply with Obamacare's protections for those people who already have pre-existing conditions under it.

Trump's new order also mentions about health reimbursement arrangements (HRA) through which employers can give workers money to buy their own coverage, CNN reported. 

The changes suggested by Trump could take six months or more to come into effect, a senior administration official said, according to CNN.

However, one glance through Twitter will show that the executive order hasn't been received well by users of the micro-blogging site. While some attacked Trump for the move, saying he did it as he hated former President Barack Obama, others are blaming the president for taking away healthcare from the poor.

A journalist tweeted how his inbox was filled with mails from medical organizations warning that Trump's executive order would ruin the healthcare market.

A user said that instead of health care Trump would provide "junk care" to the masses.

Some said that Trump's decision of dismantling Obamacare without an alternative plan is bad for Americans.

Democrats criticized the president's move, saying it would hurt the current health care markets.

Sen. Minority Leader Chuck Schumer, (D-New York), tweeted: "Having failed to repeal the #ACA in Congress, @POTUS is using a wrecking ball to single handedly rip apart & sabotage our healthcare system."

Experts said Trump's executive order will not make healthcare affordable for all Americans.

"This is a case where doing something is worse than doing nothing," Ezekiel Emanuel, an oncologist and one of the architects of Obamacare, said on CNN. "It's not going to solve the problem at all and remember, it effects a very small number of people."

"It won't do anything for a lot of the people on the exchange who are not members of franchises or trade associations," Emanuel said. "So this is more show than actual reality in terms of making health care affordable for Americans."