Syria's Assad blames 'terrorism' for regime collapse in first statement since defeat

LONDON -- Former Syrian President Bashar Assad on Monday made his first official statement since being toppled by a rebel offensive and fleeing the country for Russia, declaring that he left Syria after a request from Moscow to do so.

"My departure from Syria was neither planned nor did it occur in the final hours of the battles," Assad said in a statement attributed to him and posted to the presidency's official Telegram channel.

"As terrorist forces infiltrated Damascus, I moved to Latakia in coordination with our Russian allies to oversee combat operations," Assad said.

"Upon arrival at the Khmeimim air base that morning, it became clear that our forces had completely withdrawn from all battle lines and that the last army positions had fallen," the statement continued.

"As the field situation in the area continued to deteriorate, the Russian military base itself came under intensified attack by drone strikes. With no viable means of leaving the base, Moscow requested that the base's command arrange an immediate evacuation to Russia."

"This took place a day after the fall of Damascus, following the collapse of the final military positions and the resulting paralysis of all state institutions," Assad said.

"At no point during these events did I consider stepping down or seeking refuge, nor was such a proposal made by any individual or party," Assad said. "The only course of action was to continue fighting against the terrorist onslaught."

"At no point during these events did I consider stepping down or seeking refuge, nor was such a proposal made by any individual or party," Assad said. "The only course of action was to continue fighting against the terrorist onslaught."

Assad made no comment on the longstanding allegations that his regime committed vast human rights abuses throughout his 24 years in power, abuses that opposition forces, human rights organizations and foreign governments say only intensified after the outbreak of civil war in 2011.

The fall of his regime saw jubilant fighters and residents emptying Assad's prisons. More than 100,000 people are still believed to be missing, disappeared into Damascus' sprawling and opaque security apparatus.

The leader of the Hayat Tahrir al-Sham rebel group, which led the surprise offensive striking out of Idlib southwards towards Damascus, vowed that the transitional government would hold to account those implicated in Assad's human rights abuses.

Ahmed al-Sharaa -- also known by his nom de guerre Abu Mohammed al-Jolani -- said shortly after the fall of Damascus, "We will not hesitate to hold accountable the criminals, murderers, security and army officers involved in torturing the Syrian people."

As Assad's statement was released, rescue workers were picking through a suspected mass grave discovered on the outskirts of the capital. The area was under military control and the road leading into it was closed to civilians. A United Nations delegation, meanwhile, was visiting the infamous Saydnaya prison in the capital.

In Monday's statement, Assad described himself as a leader "who, from the very first day of the war, refused to barter the salvation of his nation for personal gain, or to compromise his people in exchange for numerous offers and enticements."

The former president said he "stood alongside the officers and soldiers of the army on the front lines, just meters from terrorists in the most dangerous and intense battlefields."

"During the darkest years of the war," Assad said he was a leader who "did not leave but remained with his family alongside his people, confronting terrorism under bombardment and the recurring threats of terrorist incursions into the capital over fourteen years of war."

"I have never sought positions for personal gain but have always considered myself as a custodian of a national project, supported by the faith of the Syrian people, who believed in its vision," he added. "I have carried an unwavering conviction in their will and ability to protect the state, defend its institutions, and uphold their choices to the very last moment."

"When the state falls into the hands of terrorism and the ability to make a meaningful contribution is lost, any position becomes void of purpose, rendering its occupation meaningless," the former president said.

"This does not, in any way, diminish my profound sense of belonging to Syria and her people -- a bond that remains unshaken by any position or circumstance. It is a belonging filled with hope that Syria will once again be free and independent."

ABC News' Somayeh Malekian, Ghazi Balkiz, James Longman and Joe Simonetti contributed to this report.