News of Libi's death first emerged on a website used by Islamist groups.The website, ekhlaas.org, said Libi had "fallen as a martyr", the Reuters news agency reports.
US intelligence agencies have been investigating reports that a top al-Qaeda figure was killed in the Afghan-Pakistan border area this week.It follows a missile attack in Pakistan's North Waziristan area in which 12 militants were reported killed.
While Western counter-terrorism officials told the BBC they believed Libi to be dead, they would not discuss how he was killed.Libi has appeared in a number of al-Qaeda videos. He is reported to be one of al-Qaeda's most senior field commanders in Afghanistan.
Reports say he was also active across the border in the Waziristan region of Pakistan.