U.S. President Barack Obama on Saturday urged Congress to pass his health reform bill, which faces a tough fight on Capitol Hill.

In his weekly radio address, Obama said Congress owed the country "an up-or-down vote" on health reform, touting the reform would bring tax credits for small businesses to purchase coverage, make it possible for people with pre-existing conditions to purchase coverage, and prevent insurance companies imposing lifetime caps or annual limits to the amount of care people receive.

"If we act now, all of this will happen this year," Obama said, warning if nothing was done this year, more Americans would lose health insurance if they switched or lost their jobs, and small businesses would be forced to choose between health care and hiring.

Obama also criticized insurance companies, which couldn't give him a "straight answer as to why they keep arbitrarily and massively raising premiums."

In order to push forward the health reform, Obama on Thursday attended a meeting called by Health and Human Services Secretary Kathleen Sebelius with the largest health insurance companies at the White House, and urged insurance companies "not to block comprehensive health insurance reform," according to White House Spokesman Robert Gibbs.

The health reform has divided Congress, with Republicans standing against it in a rock-solid position, making Democratic unity ever more important.

Obama summoned more than a dozen House Democrats to the White House Thursday, eliciting their support for his year-long healthcare efforts.