Voters in both states back regulated sale of marijuana as a recreational drug but federal ban remains

Colorado and Washington have voted to legalise marijuana in pioneering decisions that challenge the United States' decades-old war on drugs.

Voters in Colorado backed Amendment 64, which makes it legal for individuals to possess and for businesses to sell marijuana for recreational use, by 52.7% to 47.3%, prompting jubilation among yes campaigners.

Voters in Washington state backed a similar measure.

With counting still under way the fate of a similar proposal in Oregon remained unclear.

Campaigners called the Colorado and Washington votes historic.

"We went up against 70 years of lies to keep marijuana illegal for evil reasons," said Betty Aldworth, a spokeswoman for the Regulate Marijuana like Alcohol campaign. "And we took them down."

Under Amendment 64 marijuana, previously available in Colorado for medicinal purposes, will be available to anyone aged over 21 and be taxed and regulated like alcohol and tobacco.

The American Civil Liberties Union backed the measure because marijuana possession is a main reason so many Latinos and African Americans are in prison. A libertarian movement also enthused many young people to vote yes.

Many of Colorado's senior Republicans and Democrats had joined police and other officials in opposing the measure, claiming it could lure drug cartels to Colorado and make it easier for teenagers to access marijuana.

"The voters have spoken and we have to respect their will," said Governor John Hickenlooper, a Democrat. "This will be a complicated process but we intend to follow through. That said, federal law still says marijuana is an illegal drug so don't break out the Cheetos or goldfish too quickly."

Angela Robine, 25, an energy analyst in Denver, voted to legalise marijuana even though she expects federal authorities to overturn the decision. "I voted to start a national conversation on this. It's long overdue."