A message from the people of Aleppo to the world-Syria 5 Years Later.

They stand tall and proud in front of a crumbling skyline, the exhaustion of their cause written on their faces.

Dressed in the uniforms of their trades, the men hold Syrian opposition flags and a woman clutches a baby.

They are a coalition of activists consisting of doctors and civil servants from Aleppo's rebel-held areas.

In a rare video message in English, they issue a desperate plea for humanitarian aid from the US-led coalition -- via airdrop.

An English-speaking Syrian doctor known as Dr. Hamza al-Khatib stands in the middle of the group.

He runs through a grim accounting of Aleppo's misery, based on numbers from this coalition of activists:

500,000 people killed in six years, he says;

At least 271,536 people trapped inside rebel-held eastern Aleppo, he says, citing Aleppo City Council;

At least 2,300 documented strikes in the last 23 days: Airstrikes, explosive barrels, artillery, cluster bombs, bunker-busters, bombs loaded with chlorine gas;

4 hospitals struck in the last week, along with 6 schools, the civil defense headquarters and 2 bakeries.

CNN cannot independently verify the number of people killed in Syria, but the United Nations puts the figure at around 400,000.

Al-Khatib accuses Russian and Syrian regime air forces of intentionally targeting civilian infrastructure to "break people's will," though Russia has denied targeting civilian infrastructure.

Starving, dying people with little to no access to medical care are afraid to go to hospitals, he says, lest they became the victims of the latest bombing.

The past six years have been a "slow-motion train wreck," leaving him and his colleagues wondering what good is the United Nations, he says. He appeals to the international community to push for the following:

Ground Bashar al-Assad's air force or use diplomatic leverage to end Russian and Syrian bombardment of the city.

Open a demilitarized humanitarian corridor under the United Nations' control for food, fuel, medicine and infrastructure supplies for water stations, electricity, hospitals, schools and civil defense.