The US forces have narrowed the hunt for Osama bin Laden to a 40-square-mile section of the Waziristan region of Pakistan, a media report said on Monday quoting senior US officials.

Authorities are casting a net around the towns of Angoor Ada and Wana in southern Waziristan, which are infested with al Qaeda supporters, but it is a difficult and dangerous area to operate in, ABCNEWS said.

"It is hostile area in terms of geography, mountains, terrain, ravines and two ferocious tribes, the Wazirs and the Mahsuds who dominate the area," said Akbar Ahmed, professor of international relations at American University in Washington.

Taliban leader Mullah Omar is also believed to be hiding in northern Waziristan, the report said.

Officials told the network that there is new information from electronic intercepts and intelligence on the ground, which show that bin Laden is alive.

Sources in Waziristan were quoted as saying that Al Qaeda has affiliates in different cities from Wana to Karachi, who are responsible for transporting al Qaeda members and sending messages by camel, enabling bin Laden to avoid US spy planes and satellites overhead.