Breaking up the world's tech titans is not the best way to counter their power, EU Competition Commissioner Margrethe Vestager said Friday, while leaving room for that eventuality as a "last resort."

"There is a risk that with the network effects, even if we split up companies, very soon they will be big again," Vestager told reporters during a visit to Washington.

The commissioner, who hails from Denmark, offered the example of a mythological Hydra, arguing that "when you chop off the head, there are four more."

Debate has raged in Europe for years over the competitive advantage wielded by US tech giants Google, Amazon, Facebook and Apple.

Vestager has repeatedly gone after the companies for violating competition laws, demanding record fines.

The debate has moved across the Atlantic to the United States, where several scandals on how these companies use and sell users' have sparked controversy.

Democratic Senator Elizabeth Warren, who is running for president, has proposed breaking up Big Tech, saying the companies have "too much power over our economy, our society, and our democracy."

Even conservatives are calling for tougher regulations on digital giants, but others are worried that a politically motivated crackdown on firms could damage free speech protections.

"We try to deal with the tools we know very well," Vestager said.

"To us, it would be a matter of very last resort to break up a . I'm being told we would have the legal basis to be able to do that, if the case was strong enough," she noted.

"We can use the tools we have to a very large degree and push them... so that we make sure prices are low, make sure that innovation is protected."