WASHINGTON — The knockoff designer bags look close enough to the real thing that few would notice at a glance. Same goes for the imitation replica football jerseys or popular boots. And the online prices seem too good to pass up.

But the products are fake and the websites selling them are breaking federal law by selling copies of high-end merchandise without giving credit or money to the real designers and creators. And while the products can look as good as the real thing, buying fake merchandise can be dangerous, authorities warn.

“Not only is this is a direct threat to American innovation … but it’s also a public safety issue,” Immigration and Customs Enforcement Director John Morton said Monday as he announced that the government had shut down 150 websites accused of selling counterfeit merchandise.

Attorney General Eric Holder and Rebecca Blank, acting deputy Commerce secretary, were set to launch a campaign Tuesday to alert the public to the dangers of buying counterfeit goods.

“This is increasingly not simply a matter of ‘mom and pop’ violations at the corner of Fourth and Main,” Morton said Monday. “We are worried about organized crime and (that profits) are going to fuel other criminal activity.”

Morton would not say if organized criminal groups are suspected of running any of the seized sites to help fund other criminal acts.

Some counterfeit goods, including medications and electronics, can also pose a health risk, Morton said.

Morton and Assistant Attorney General Lanny Breuer, who leads the Justice Department’s criminal division, said that in the latest crackdown, federal authorities seized 150 website domain names where fake goods were being sold to unsuspecting bargain hunters.