WASHINGTON — Nearly two days after a bomb killed his top aides, Syrian President Bashar Assad has failed to emerge.

Assad has not been seen in public or addressed his country since at least three of his top aides were killed in a bombing on July 18. Assad’s younger brother, Maher, regarded as the architect of the war on Sunni rebels, has also not been seen.

“We’re not 100 percent sure where he is,” U.S. State Department spokesman Patrick Ventrell said.

On July 19, Syrian state television showed images of what it said was Assad speaking to his new defense minister, Gen. Fahd Jassam Al Freij, the outgoing military chief. But in an unusual omission, the television did not show the swearing-in ceremony for Al Freij, who succeeded Daoud Rajiha. Rajiha was killed in the bombing in the National Security Agency in Damascus.

“The footage released was not that of Assad’s office in Damascus,” a Western analyst who monitors Syria said. Earlier, Western intelligence sources said Assad left for Latakia after the bombing. They said Assad as well as Maher were believed to have been injured in the attack.

Maher, commander of the Syrian Army’s 4th Division, has also not been heard from since the explosion. Maher, regarded as the No. 2 member of the regime, was responsible for the war against Sunni rebels. “We’ve been saying consistently for some time now that the Assad regime is not going to survive this,” Ventrell said during a July 19 briefing. “And so we’re planning on that political transition.”

Opposition sources have asserted major gains in the rebel war against Assad. On July 19, the Syrian Observatory for Human Rights said rebel forces seized control of much of the Damascus neighborhood of Mezzeh as well as parts of the Syrian border with Iraq and Turkey. “Rebel forces are now in full control of the Basateen Al Mezzeh area after regime troops retreated,” the London-based opposition group said. “Clouds of black smoke were seen rising from Mount Qasyoun, which overlooks Damascus.”

The Assad regime has asserted that rebels were attacking government targets in Damascus dressed in the uniform of the Republican Guard. The guard has been responsible for regime security, and at least one brigade was decimated by massive defections.

“Gunmen are wearing Republican Guard uniforms in the neighborhoods of Tadamon, Midan, Qaa and Nahr Aisha, proving that they are planning attacks and crimes,” the official Syrian news agency, Sana, said. The United States has been urged to intensify military support for the rebels, particularly the Free Syrian Army. A leading American analyst said the death of Assad’s brother-in-law, Assaf Chawkat, deputy defense minister, and other regime members would force Assad to reorganize his command.

“Washington should build on the Damascus attack to hasten the regime’s collapse, focusing on the dangerous period marked by Assad’s last stand and the emergence of whatever comes next,” Robert Satloff, executive director of the Washington Institute for Near East Policy, said. (Copyright © 2012 East West Services, Inc. 07/20/12)