Two New Jersey lawmakers proposed Thursday to raise their state’s minimum age for buying cigarettes to 21, reaching across the Hudson River to borrow an idea from New York City in a gesture of regional cooperation to keep tobacco from many young adults.

In the unusual move that highlighted a spirit of alliance between sometime rivals, New Jersey state Sen. Richard Codey and Assemblyman Ruben Ramos unveiled the proposal at New York’s City Hall.

“I think we have to send a message to our young adults: to smoke is no joke,” said Codey. As acting governor, he signed a measure raising the age limit from 18 to 19 seven years ago.

While the threshold already has been raised to 21 in two Boston suburbs, the idea has gained more attention since City Council Speaker Christine Quinn and colleagues proposed it in the nation’s biggest city last month. Some state lawmakers have since proposed doing likewise throughout New York. The minimum age is currently 18 in the city and state, although some New York counties have boosted it to 19.

“This has now truly become a regional, if not national, effort,” said Quinn, who noted that a Chicago alderman also has expressed interest in the idea since it was broached in New York City. It had been proposed in the Texas Legislature earlier this year.

Under federal law, no one under 18 can buy tobacco anywhere in the country.

Advocates say higher age limits help stop, or at least delay, young people from developing a habit that remains the leading cause of preventable deaths in the U.S., despite decades of efforts to call attention to its dangers. The measures make it tougher for 18-to-20-year-olds to obtain cigarettes for themselves and for younger friends, supporters say.

Altria Group Inc., which produces the top-selling Marlboro brand, suggested that the proposal would “restrict adult consumers’ access to legal products,” while noting that it hadn’t seen details.

“We have encouraged state and local governments, along with our retail customers, to vigorously enforce existing minimum age requirements,” and Richmond, Va.-based Altria supported setting the federal minimum age at 18, spokesman David Sutton said in a statement.

A representative for R.J. Reynolds Tobacco Co., maker of brands including Camel, didn’t immediately respond to phone and email inquiries.

Higher age limits have faced criticism from smokers’ rights advocates who feel the restrictions are unfair and patronizing to an age group considered old enough to make such adult decisions as voting and serving in the military. Manufacturers and some retailers have suggested young adult smokers may just turn to black-market merchants or to nearby areas with lower age limits.

The New York and New Jersey advocates say that’s a good reason to set the limit at 21 region-wide.

New Jersey raised the limit to 19 in 2006, in tandem with a considerably more controversial measure that outlawed smoking in bars, restaurants and most other indoor public places. Codey and Ramos said they planned to introduce the 21-year-old limit formally in the state Legislature on Monday.

The measure is progressing in New York’s City Council, with a vote likely sometime this summer. Mayor Michael Bloomberg, who had opposed higher age limits in the past, supports the current plan.

(AP)