For years, Abdullah al-Omar rubbed shoulders with some of the most powerful people in Syria.

In case there is any doubt, he is quick to show photos in his phone as proof.

Scores of photographs show the corpulent Syrian beaming and shaking hands with government ministers, foreign dignitaries, and even the Syrian president.

"He knew me by name," al-Omar said, pointing to a photo of himself standing with Bashar al-Assad. "One day we were sitting at a table and he fed me with his own hand and said to me, 'You love food since you are from Aleppo.' Then he said to his escort, 'Take special care of Abdullah al-Omar because he loves food and his stomach.'"

Al-Omar claims that for five years he worked in the press office of the presidential palace in Damascus, as part of a 15-person team under the direction of long-time government spokeswoman and presidential adviser Bouthaina Shabaan.

Until he defected and fled the Syrian capital last month, al-Omar said, the bulk of his work consisted of lying.

"Our job was to fabricate, make deceptions and cover up for Bashar al-Assad's crimes," he said.

It is impossible to independently confirm al-Omar's claims. The fact that he freely admits to a career as a government propagandist makes him a somewhat unreliable whistle-blower.

However, the editorial director of a pro-rebel media organization who asked not to be named for security reasons confirmed to CNN that he knows al-Omar worked for Syrian secret police.

"He is the biggest informant for the Al Jawiya," the Syrian journalist said, referring to Syria's much-feared air force intelligence agency. "He was a very strong informant who worked for the palace and worked for Bouthaina (Shabaan)."

During a four-hour interview in Istanbul, al-Omar described in detail some of the propaganda methods used by pro-government media.

During the government's artillery bombardment of the rebel-held neighborhood of Baba Amr in the city of Homs, loyalist women were brought in and disguised as locals for government television interviews, he said.

"The women would say that the massacres against men, women and children were perpetrated by armed gangs, when it was actually the Syrian regime, security forces and the Shabiha" -- the pro-government militia -- "who were behind these horrendous acts," al-Omar said.

These claims are backed by the accounts of residents of Homs, who spoke to CNN on condition of anonymity for fear of reprisal at the hands of Syrian security forces.

"I remember that day as if it was yesterday, when state TV showed Assad parading through Baba Amr, not a single resident was from the area," said a native of Homs, now exiled to neighboring Lebanon. "They brought them from neighboring towns from the countryside so they could pretend he was getting a hero's welcome, that he was greeted as a beloved leader, when in reality everyone in Homs knew he was behind the destruction of every house and the killing of every innocent civilian on Homs and every other city in Syria."

After protests erupted against the government in March 2011, al-Omar said, he was ordered to establish a pro-regime TV station in Aleppo.

A commercial on a Syrian website shows al-Omar holding a microphone in front of a banner advertising "Al Aleppia TV." Journalists in Aleppo said the station was a cheaply run operation that broadcast over the Internet.

One of Omar's assignments was to book pro-regime guests on his TV channel, as well as on larger international networks, to discredit defectors from the Syrian government.

"We would contact regime loyalists from Lebanon or Syria to appear as guests on Al Jazeera, Al Arabiya and other channels, to say these defectors are bad, corrupt, and not doing their jobs well."

Asked how his former colleagues would react to his own defection, al-Omar said, "they will follow standard procedure and say Abdullah al-Omar has nothing to do with the press office, and doesn't work in the presidential palace, and that they never heard of me and that I descended from heaven just to smear the image of the regime.

"But what will embarrass them," he continued, "is that I appear in a lot of pictures and videos, practically in all the press conferences for Bashar al-Assad and his official reception ceremonies."

There is ample photographic evidence to back this claim.

In more than a dozen photos, al-Omar is clearly seated at press conferences featuring al-Assad and a number of visiting heads of state, including Iranian President Mahmoud Ahmadinejad, former Russian President Dmitry Medvedev, and Venezuelan President Hugo Chavez.

Pictures also revealed al-Omar at the presidential palace and at what appear to be government receptions, posing alongside high-ranking officials like Shabaan, Syrian Foreign Minister Walid Moallem, and top members of the Syrian parliament and ruling Baath political party.

Al-Omar was also photographed alongside regime allies such as Palestinian Hamas leader Khaled Mashaal, the Iranian ambassadors to both Damascus and Beirut, and a bearded man al-Omar identified as the head of the politburo of Hezbollah.