WASHINGTON — (CNN) The evacuation of thousands of refugees out of the besieged city of Aleppo has been halted and the status of the operation thrown into doubt, the International Committee of the Red Cross confirmed Friday.

ICRC staff, Syrian Red Crescent workers and representatives of the World Health Organization have been told to leave eastern Aleppo.

“The evacuations have been halted,” Middle East spokesman for the ICRC, Ralph El Hage, told CNN.

“We are hoping the parties reach an agreement so we can move forward with the evacuation.”

Syria’s state news broadcaster reported that the Al-Nusra front had blocked the exit of 1,250 civilians in Aleppo.

Citing the temporary suspension, the state broadcaster said the evacuation had stopped because there was a breakdown in the ceasefire when some of the evacuees were transporting weapons and advanced communication devices.

The United Nations’ Jan Egeland expressed his frustration, tweeting: “Very successful evacuations from East Aleppo have been discontinued. Thousands of civilians, including orphans, are still waiting to escape.”

Activist Mahmoud Raslan, who is inside Aleppo, told CNN that he was close to the entrance gate from rebel-held to regime-held areas when violence flared.

“The evacuation was suspended by the regime and the Syrian regime now is shooting at the entrance point using heavy machine guns,” he said.

“A warplane is in the sky now and the Syrian regime is trying to advance in al-Sendyanah bridge, people are gathered in huge numbers and very scared.”

The activist Aleppo Media Center blamed the suspension of the evacuations on Iranian militias, who they say targeted the road leading into east Aleppo’s Sukkari district with heavy gunfire.

Mahmoud Zaza, a medic in eastern Aleppo, said the need for assistance was critical.

“There are only three doctors left including me,” he told CNN.

“We have 30 cases which need immediate evacuation.”

Up to 9,000 people have already been taken out of the besieged city in nine convoys since Thursday, including 108 wounded, according to Russian and Syrian state media.

For many of those leaving, their destination will be the rebel-controlled Syrian province of Idlib — which will likely be the next target of Syrian President Bashar al-Assad’s regime.

An activist working inside the city broke down talking to CNN reporters on Friday, saying he wasn’t sure if his children would ever return to Aleppo.

“We waited for the international community and the United Nations to punish the criminal and not the victims (the people). Unfortunately the punishment was for the people. They have displaced us from our land,” he said.

“Honestly I don’t know if we can return back someday to our land or if it is going to be like the fate of the Palestinians.”