The brother of al-Qaeda head Ayman al-Zawahiri has reportedly been arrested by Syrian military forces in the city of Dara'a, southwest of the capital Damascus.
The 59-year-old Mohamed al-Zawahiri was arrested while he was meeting opposition militants in Dara'a, the English newspaper The Independent
reported on Friday.
According to the daily, Western intelligence agencies fear the arrest could lead to the detention of more al-Qaeda members in Syria.
Zawahiri spent 14 years in prison in Egypt on charges of being involved in the assassination of former president Anwar Sadat in 1981 and taking part in terrorist acts.
Ayman, 61, became the head of al-Qaeda in 2011. In May 2011, US Navy SEALs claimed they killed former al-Qaeda leader Osama bin Laden in Pakistan.
Ayman has called for military action against the Syrian government.
Reports say hundreds of al-Qaeda terrorists are active in Syria under the banner of the al-Nusra Front group.
Last month, the US State Department designated the al-Nusra Front group as a terror organization linked to al-Qaeda in Iraq.
Turkey, Qatar, and Saudi Arabia are reportedly arming and funding militants fighting the Damascus government to implement Western plans in the Arab county.
Syria has been experiencing unrest since mid-March 2011. Many people, including large numbers of security personnel, have been killed in the violence.
The Syrian government says the chaos is being orchestrated from outside the country, and there are reports that a very large number of the militants fighting the Syrian government are foreign nationals.
Several international human rights organizations have accused the foreign-sponsored militants of committing war crimes.