The few remaining doctors tending to patients in besieged areas of eastern Aleppo have appealed to US President Barack Obama to intervene and provide assistance to more than 250,000 people trapped in the area.

In a petition signed by 15 physicians, the White House has been urged to open a permanent lifeline to Aleppo. "We do not need tears or sympathy or even prayers, we need your action. Prove that you are the friend of Syrians," the doctors wrote in the petition.

They even mentioned that if the attacks on medical establishments continue at the current rate there will be no hospitals left in the city in a month.

The plea comes after the Russian government announced three-hour daily ceasefires to allow humanitarian aid into the city.

At a briefing in Moscow, General Sergei Rudoski, a senior Russian defense official said on Wednesday that military action, artillery and air strikes will be halted from 10am to 1pm local time. The United Nations immediately said that three hours is not long enough to help the people and asked for 48 hours of ceasefire.

In the heart wrenching letter, the doctors said that since the revolt against President Bashar al-Assad began, they have "borne witness as countless patients, friends and colleagues suffered violent, tormented deaths". The doctors said that although they have vowed to help those trapped in Aleppo, the US President should "do his duty as well".

"For five years, the world has stood by and remarked how 'complicated' Syria is, while doing little to protect us. Recent offers of evacuation from the regime and Russia have sounded like thinly veiled threats to residents – flee now or face what fate?"

The doctors further urged Obama "to act now to stop the bombs that continue to fall on the city and ensure they are never held under siege again". At least one hospital is attacked every 17 hours in the area and doctors are often left with no option but to let children die due to shortage of blood, medical supplies and advanced scanners, the Guardian reported.

"What pains us most, as doctors, is choosing who will live and who will die. Young children are sometimes brought into our emergency rooms so badly injured that we have to prioritise those with better chances, or simply don't have the equipment to help them. Two weeks ago, four newborn babies gasping for air suffocated to death after a blast cut the oxygen supply to their incubators. Gasping for air, their lives ended before they had really begun," the letter read.

Aleppo civilians
Civilians breathe through oxygen masks at a hospital after a civil defence group said a gas, believed to be chlorine, was dropped alongside barrel bombs in a neighbourhood in Aleppo on 11 August 2016 REUTERS/Abdalrhman Ismail