The Syrian army prepared Tuesday to direct a new volunteer military corp to fend off rebel attacks against President Bashar al-Assad. The move is aimed at growing Syria's military amid an ongoing civil war that has killed thousands and displaced millions. 

"In response to the rapid development of events, to support the successes of armed forces and to meet people's wishes to put an end to terrorist acts in the Syrian Arab Republic, the general command of the armed forces announces the formation of a Fifth Attack Troop Corps of volunteers," an army statement said.

Syria requires men who are at least 18 years old to serve in the army, which counted 300,000 members before the war. Men were asked to serve two-year terms before the conflict began, but many have complained of a never-ending service under the war. Some have deserted the army, or paid bribes to get out of the draft. 

The new volunteer corp will include men over 18 years of age not already eligible for military service. Deserters cannot join, Reuters reported Tuesday.

The Syrian military also called on rebels in east Aleppo Tuesday to leave the area amid a campaign to take back the city, Agence France-Presse reported. They spread the word by airdropping leaflets in rebel-controlled neighborhoods.

"To those involved in carrying weapons, we stretch out our hand to you. Reserve your place before it is too late," the leaflets read.

The war began as a peaceful opposition movement to Assad inspired by the Arab Spring in March 2011. It has since left more than 250,000 people dead and fueled a global refugee crisis. More than 4.8 million people have fled Syria to Europe or neighboring Lebanon, Jordan and Turkey.

Syria has teamed up with Russia, Iran-backed militias and fighters from Lebanon's Shiite Muslim Hezbollah group to wipe out rebel groups angling to unseat Assad. Roughly 250,000 Aleppo residents are stuck in the cross-fire. United Nations humanitarian chief Stephen O'Brien said Monday the Syrian government has put nearly one million people across the country at risk because of its offensive campaign.

"Civilians are being isolated, starved, bombed, denied medical attention and humanitarian assistance in order to force them to submit or flee," he told the UN Security Council.

Assad succeeded his father, Hafez, in 2000.