A purported audio message from the leader of al-Qaida in Iraq says the Islamist al-Nusra Front fighting the forces of President Bashar al-Assad in neighboring Syria is branch of its organization.
The message said to be from Abu Bakr al-Baghdadi was posted on jihadist forums, and says the groups will jointly go by the Islamic State of Iraq and the Levant.
The authenticity of the message could not be confirmed.
The link between al-Nusra and al-Qaida had been suspected, leading the United States in December to designate al-Nusra a terror group.
The organization has claimed responsibility for suicide bombings in Syria.
Meanwhile, the Syrian government said it has rejected a request by United Nations chief Ban Ki-moon to allow a team of inspectors to investigate reports of chemical attacks in the war-torn country.
Syria's foreign ministry said Monday the government is only willing to allow the inspectors into the village of Khan al-Assal, near Aleppo, where the rebels were alleged to have used chemical weapons last month. It said Ban wants inspectors to deploy throughout the country. The ministry said this would be a violation of Syrian sovereignty
Ban has said an investigating team is ready to deploy in Syria within 24 hours.
Both the government and rebels opposed to President Assad have traded accusations about the use of chemical weapons.