It's a place to buy and sell illegal drugs, human organs and weapons, and it's all taking place in the shadowy depths of the Internet known as the dark web.

Social networking giant Twitter has issued warnings to some users, notifying them their accounts may have been targeted by state sponsored attacks.

French authorities want to ban the use of public Wi-Fi networks when a state of emergency is declared, in hopes of cracking down on terrorists using the networks for communication, reports say.