KABUL (AFP) - The United States is erecting billboards in Afghanistan offering hefty rewards for Osama bin Laden, Taliban chief Mullah Mohammad Omar and US Al-Qaeda member Adam Gadahn, the embassy said Saturday. Ten of the large Rewards for Justice boards were being erected countrywide, two of them in Kabul, embassy spokeswoman Corina Sanders told AFP. They show a portrait of the turbaned Gadahn flanked by those of Al-Qaeda chief bin Laden and Mullah Omar. The United States led an invasion of Afghanistan in late 2001 that toppled the extremist Taliban regime because it did not surrender Al-Qaeda leaders after the September 11 attacks on Washington and New York. It has tens of thousands of troops in Afghanistan searching for the fugitives, whom Afghan officials claim are across the border in Pakistan, but they remain elusive. The US government's Rewards for Justice website offers up to 25 million dollars for information leading to the arrest of bin Laden, 10 million for Mullah Omar and one million for Gadahn. "We are doing this because we believe there is a lot of untapped information here in Afghanistan," Sanders said. "We are using the Rewards for Justice programme to facilitate the finding the whereabouts of these people but also the leadership of these kind of organisations," she said. The US government had also been running ads on radio and television with a call number active for a few months, she said. "We are receiving phone calls," she said, without being able to give information.