BEIRUT -- The U.N. said Friday an estimated 31,500 residents have been displaced following Syrian government advances into the besieged eastern Aleppo enclave this weekend, as government media reported from those newly-captured areas, demonstrating its restoration and resettlement efforts there.

The advance of government and allied troops was one of the most dramatic shifts in the conflict now in its sixth year, as their troops marched into areas controlled by the opposition since 2012. Losing eastern Aleppo would cost the opposition its most significant urban presence.

As the government advances, airstrikes and shelling continued, rendering the situation in the besieged area even more direful. The U.N and rights groups have urged for a pause to allow humanitarian access to the enclave's estimated 275,000.

Meanwhile, world leaders paid lip service to calls for a cease-fire. There were no signs that one would materialize soon.

The Turkish and German foreign ministers were among those who called for a ceasefire in Aleppo during their visits to Beirut on Friday.

Speaking in Beirut at a joint press conference with his Lebanese counterpart Friday, Turkish Foreign Minister Mevlut Cavusoglu said a cessation of hostilities should be announced "as soon as possible, immediately."

Germany's Foreign Minister Frank-Walter Steinmeier also called for "temporary truces" in Syria to allow for a humanitarian corridor.

Fighting however continued on the edge of the eastern Aleppo enclave, as allied government troops made progress in their advance on the southern and eastern fronts. Meanwhile, rebel rockets striking government controlled areas of Aleppo killed four Friday, according to state media.

Over the weekend, allied government troops advanced from the northern side, capturing nearly half of the 45-square kilometre enclave (17 square miles) and sending the local population fleeing.

Most of those displaced fled to government and Kurdish-held areas in western Aleppo, separated only by roads and deserted buildings. Many were also displaced inside rebel-held parts of the city, cramming into already crowded and damaged areas in south and central eastern Aleppo.

Syrian state media reported from the government-controlled areas. State broadcaster al-Ikhabirya TV showed hundreds of displaced people sitting on rain-soaked streets and interviewed the newly-displaced residents lodged in empty buildings pockmarked with bullets. Their fresh laundry hung on the walls overlooking the streets. The state-owned channel showed dozens of the displaced people waving Syrian flags from green government buses.

The Syrian government has been keen to show it is restoring normalcy to the shell-shocked community following the swift restoration of government control to areas held by the opposition for four years. Syrian officials visited the newly-captured areas as workers were filmed clearing debris.

An Ikhbariya broadcaster said work is underway to soon reopen a road linking the eastern and western parts of the city, disused for years. He also interviewed newly-resettled residents, who spoke of rebel abuses.

One displaced woman interviewed in the government-held Jibreen district said her son was shot dead as he fled rebel areas. The woman, who didn't give her name, said she would carry a gun to avenge her son's killing. She praised the Syrian army and said that while in rebel-held areas her family had no food or drink and was treated badly.

"My son Bashar died hungry," she said in tears.

Others interviewed in the newly captured Hanano district complained of being mistreated on suspicion of co-operating with the Syrian army, including one who said he was detained. One resident complained of a lack of heating facilities in their new settlement.

Opposition and activists had also accused the government of shelling displaced Syrians who were fleeing the government advances. At least 50 people were killed in artillery shelling of the rebel-held district to which they were fleeing.

The Office of Coordination of Humanitarian Affairs estimated that a total of 26,500 people had fled to government-held Jibreen, east of Aleppo, and Kurdish-held Sheik Massoud. Another 5,000 were displaced within eastern Aleppo.

Spokesman Jens Laerke on Friday cited reports that some men and boys trying to enter government-controlled western Aleppo had been detained by government troops. London-based rights group Amnesty International said it too had received reports of Syrian security forces detaining men in Aleppo areas recaptured by the government and warned of the potential for revenge attacks. The reports could not be independently confirmed and a Syrian military official said screening measures were in place to prevent "terrorists" infiltrating the civilians.

U.N. officials have expressed concern over the plight of civilians caught in the fighting in Aleppo, and called for more access to the eastern part of the city that has been besieged since July. There have been no operational hospitals in eastern Aleppo for nearly two weeks after they were bombed.

Meanwhile, the Russian military said it has been the only source of food, medicine and other supplies for 90,000 residents of the city's neighbourhoods seized by the Syrian army, criticizing the U.N. for dragging its feet on delivering humanitarian aid there.

The U.N. has said local partners have provided hot meals and drinkable water to those displaced in government-controlled Jibreen and urged the Syrian government to ensure that U.N. staff are able to deploy unrestricted and safely across Aleppo.

Associated Press writers Jamey Keaten in Geneva and Vladimir Isachenkov in Moscow contributed to this report.