UPDATE 2-Obama signs landmark law to regulate tobacco

* New law allows tough new FDA limits on tobacco

* Tobacco blamed for 440,000 U.S. deaths per year

* Companies say will comply with regulations (Adds quotes from Obama, comments from industry)

By Jeff Mason

WASHINGTON, June 22 (Reuters) - President Barack Obama, citing his own struggle to give up smoking, signed a law on Monday giving the U.S. government broad regulatory power for the first time over cigarettes and other tobacco products.

Obama said the law would curb the ability of tobacco companies to market their products to the young.

"Almost 90 percent of all smokers began at or before their 18th birthday," Obama said at a White House ceremony before signing the bill.

"I know -- I was one of these teenagers, and so I know how difficult it can be to break this habit when it's been with you for a long time."

Obama's spokesman, Robert Gibbs, said Obama's smoking habit was "something that he continues to struggle with." He declined to answer directly whether the president still smoked.