Al-Qaida's leader has voiced support for the Syrian uprising against President Bashar al-Assad and called on Muslims from neighboring countries to come to the aid of Syrian anti-government rebels.

In a video posted Sunday on an Islamist website, Ayman al-Zawahiri urged Muslims in Iraq, Jordan, Lebanon and Turkey to join the uprising against what he called Mr. Assad's “pernicious, cancerous regime.” He also called on Syrians not to rely on the West or Arab governments.

Senior Iraqi officials say intelligence over the last four months has revealed a flow of al-Qaida-linked fighters, as well as weapons for Mr. Assad's opponents, from northern Iraq into Syria.

Zawahri's comments came a day after two suicide car bombers struck security compounds in Aleppo, a Syrian city that had been relatively peaceful throughout the uprising. While no group has claimed responsibility, suicide bombings are a hallmark of al-Qaida.

Also Saturday, a Syrian general and military physician was assassinated outside his Damascus home. Brig. General Issa Kholi is believed to have been one of the highest-ranking military officers killed in the 11-month-old conflict.

Assassinations have been a frequent component of the Syrian conflict, with each side accusing the other of targeting individuals. A spokesman for the rebel Free Syrian Army denied the insurgent force was involved in the general's killing.

Syria's turmoil began with peaceful protests against Mr. Assad's rule, but the revolt has grown increasingly militarized as army defectors and protesters have taken up arms against the government.

Zawahiri took command of al-Qaida after Osama bin Laden was killed by U.S. special forces in a raid in Pakistan in May.

Last week, he appeared in another video to announce that the Somali-based militant group al-Shabab had joined the radical, Islamist terror network.

Al-Shabab had previously said it is aligned with al-Qaida, and in June pledged allegiance to Zawahiri. The United States has designated al-Shabab a terrorist group.