The US president has criticised health insurance companies in the country for raising their premiums and denying coverage to the critically ill.

Addressing a rally in Philadelphia on Monday, Barack Obama called on the Democratic Party to back his healthcare bill, accusing some companies of dropping "more people's coverage when they're sick and need it most".

"The other day, on a conference call organised by Goldman Sachs, an insurance broker told Wall Street investors that [health] insurance companies know they will lose customers if they keep raising premiums," Obama said.

"But since there's so little competition in the insurance industry, they're OK with people being priced out of health insurance because they'll still make more by raising premiums on the customers they have.

"They will keep doing this for as long as they can get away with it."

Expanding coverage

Obama's Democratic supporters are stepping up the pressure on both the Congress and Senate to pass a delayed healthcare overhaul.

The propose change would reshape the $2.5 trillion insurance industry by cutting costs, regulating insurers and expanding coverage to tens of millions of Americans who have no health insurance at all.

Al Jazeera's Patty Culhane said the Republicans had been able to split the Democrats over the bill.

"One of the key issues that is facing Democrats right now is the issue of a government funding of abortion 

"That is such a minor provision, I think it's only 10 pages when you look at this 2,000-page bill. But the Republicans have been able to target this and there are about a dozen Democrats in the House who've said 'if we have to adopt the Senate language on abortion, we're not gonna vote for it'.

"And in this case, every single vote counts."

Congress has passed two versions of the proposed health reform, but efforts to merge the two and send a final version for Obama to sign into law collapsed in January.

The collapse followed a special election in Massachusetts, which cost the Democrats the crucial 60th Senate vote needed to overcome Republican procedural hurdles.

But Democrats are planning to use a special procedure that would allow them to pass the bill with a simple majority.