WASHINGTON - Senate Majority Leader Mitch McConnell, R-Ky., and Sen. Tim Kaine, D-Va., on Monday introduced a bill to raise the federal minimum age to purchase tobacco from 18 to 21, a measure that they say is aimed at reducing teen use of e-cigarettes.

The move, from senators from two tobacco-producing states, reflects growing concern that the popularity of e-cigarettes among teenagers threatens to reverse what had been decades of declining youth smoking rates.

"Today, we are coming together to side with young people's health," Kaine said in a statement. "With this bipartisan legislation, Senator McConnell and I are working to address one of the most significant public health issues facing our nation today."

McConnell said smoking should be part of a national debate about children's health.

"We've heard from countless parents who have seen the youth vaping crisis firsthand," McConnell said in a statement. ". . . Together, Senator Kaine and I are addressing this public health crisis head-on. By making it more difficult for tobacco products to end up in the hands of middle school and high school students, we can protect our children and give them the opportunity to grow and develop into healthy adults."

Kentucky and Virginia are the second- and third-highest tobacco producing states, after North Carolina, which accounts for almost half of the 533 million pounds produced in 2018, according to U.S. Department of Agriculture data. That year, Kentucky produced a quarter of the nation's crop, compared with Virginia, at 8%.

Meanwhile, Kentucky and West Virginia have the highest rates of deaths caused by smoking, according to the Centers for Disease Control and Prevention.

The backing of McConnell means the bill, known as the Tobacco-Free Youth Act, is likely to get a vote on the floor after vetting by the Health, Education, Labor and Pensions Committee, of which Kaine is a member.

Altria, the Virginia-based parent company of Philip Morris USA and minority stakeholder in e-cigarette producer Juul Labs, supports federal legislation to raise the tobacco purchase age, according to spokesman David Sutton.

The American Heart Association and the American Lung Association back the bill, and Matthew Myers, president of the Campaign for Tobacco-Free Kids, said he needs more time to review it.

He reiterated the organization's support for the Tobacco to 21 Act introduced last month by Sens. Dick Durbin, D-Ill., Brian Schatz, D-Hawaii, Todd Young, R-Ind., and Mitt Romney, R-Utah, which would also raise the tobacco purchase age to 21. It's also important to crack down on flavored tobacco products, including menthol cigarettes, Myers said.

"Raising the tobacco age to 21 is one important component of a comprehensive strategy to reverse the youth e-cigarette epidemic and continue reducing tobacco use in the United States," Myers said in a statement.

McConnell and Kaine spoke on the Senate floor Monday about tobacco's complicated history in their states, from the role it played in settling Jamestown to its link to slavery. Gilded tobacco leaves encircle the ceilings of the legislative chambers in Richmond, Virginia.

"Farming tobacco put shoes on kids' feet, it put dinner on the table," McConnell said. "It's a central pillar of our state's history."

Fourteen states and the District of Columbia have raised the tobacco sale age to 21, including Virginia and Maryland, which are poised to enact their laws later this year, according to the Campaign for Tobacco-Free Kids.

The federal law would make it illegal to sell a tobacco product to any person under 21 years old in all states. It would include military personnel, a category that is exempted in some states that have already raised the legal age.

Under the legislation, states that do not comply risk losing federal substance abuse block grant funding; a retailer who sells tobacco to anyone under 21 would be in violation of federal law.

The Food and Drug Administration this year issued a policy designed to combat what the agency's director has called "an epidemic" of teen vaping by restricting how and where flavored e-cigarettes are sold.

The CDC reports the number of middle and high school students using e-cigarettes rose from 2.1 million in 2017 to 3.6 million in 2018 - a difference of about 1.5 million young people. About 20% of high school students said last year that they used electronic cigarettes in the past month, compared with 1.5% in 2011.

As Virginia's governor in 2009, Kaine signed into law a bill that banned smoking in bars and restaurants, and he signed an executive order to ban smoking in state buildings and vehicles.