SAN DIEGO -- Democrat Barack Obama on Sunday promised Hispanic Americans, a key voting bloc, to press for immigration reform and improved access to health care in his first year if elected to the White House.

"The system isn't working when 12 million people live in hiding, and hundreds of thousands cross our borders illegally each year," Obama told the 40th annual National Council of La Raza convention, an influential Latino group.

"I fought with you in the Senate for comprehensive immigration reform, and I will make it a top priority in my first year as president," he said.

Obama laid out his stance on health care, status of illegal migrants and small businesses, and acknowledged that the Hispanic population in the United States, numbering some 44 million in all, will be key to his bid to defeat Republican John McCain.

"Make no mistake about it: the Latino community holds this election in your hands. Some of the closest contests this November will be in states like Florida, Colorado, Nevada and New Mexico, states with large Latino populations."

In his 30-minute speech, Obama vowed to "take on the drug and insurance companies, cut costs, guarantee health insurance for anyone who needs it and make it affordable for anyone who wants it."

He also said he has a plan to "help more employers provide health benefits for their workers," adding it was an "idea championed by my friend Hillary Clinton, who's been leading the way in our battle to insure every American."

"But I can't do this alone, so I'm here today to ask for your help," he told the crowd of 2,000.

"Just think how powerful you could be on November 4th if you translate your numbers into votes."

His rival, McCain, is set to address the convention on Monday.

A Gallup survey earlier this month showed Obama enjoys 59 percent support among Hispanic registered voters nationwide.