To crack down on Muslim extremists, one place authorities in Great Britain are looking harder at is the Internet because potential terrorists can learn how to make bombs, sneak through airport security or even murder a U.S. soldier without ever leaving home.

"This is a real problem because these sorts of extremists, Internet-types are a very, very direct incitement," said British Prime Minister Tony Blair (search).

English authorities have been extra vigilant since terrorists struck London's transit system last month. The July 7 London bombings killed 52 people and all four bombers on three underground trains and a double-decker bus. The botched July 21 attacks were an attempt to repeat the earlier bombings but nobody was killed.

Experts say that one of the most worrying aspects is that orders can be encrypted in videos or programs that Islamists can download and decipher. On Wednesday, Arabic television network Al-Arabiya aired a videotape purportedly from Al Qaeda that showed terrorists training for attacks on the U.S. and on coalition troops in Afghanistan.

Internet chatrooms can also provide secret hideaways in which to hatch plots — for example, the terror network in the Netherlands involved in the killing of filmmaker Theo van Gogh (search) last November and accused of plotting other terrorist attacks in Holland met regularly on Yahoo chatrooms.

But cracking down will not be easy. Anti-terrorism analysts say that conducting an online war against extremists would be difficult due to a lack of language experts.

"It begins with things like not having enough translators in the security services," said Peter Neuman, a terrorism expert at Kings College in London. "So there's a lot of material that doesn't get translated, so we don't even know what they are talking about."

A man U.S. officials have called an Al Qaeda (search) spokesman in London told FOX News that the Internet is not the lifeblood of the jihad movement. When it comes to the extreme hardcore, he said they don't communicate at all except for in the confines of their small cells scattered all over the world.

What the British government is doing, the spokesman said, is using the Internet as a scapegoat.

But experts say that the extremists' selective presentation of the facts amounts to incitement.

"Most of these videos show 15 minutes of Muslims all over the world suffering apparently at the hands of Western powers," said professor Michael Clark, a terrorism expert and director of the International Policy Institute in London.

"And then they show the other side of it, attacks on the West, bombs going off in Iraq and this is presented as a freeing of the world of Islam from the humiliation of this constant oppression from the West."

Click in the box near the top of the story to watch a report by FOX News' Amy Kellogg.