ALEPPO, Syria / BEIRUT / BRUSSELS: A “humanitarian pause” in the Syrian army’s assault on Aleppo took effect Thursday, but despite a drop in violence there was little sign residents were heeding calls to leave.

Moscow said the truce would be extended by 24 hours and the U.N. hoped to carry out the first medical evacuations from Aleppo Friday.

The unilateral cease-fire began at 8 a.m. with the aim of allowing civilians and fighters to evacuate the city’s opposition-controlled east.

After the pause began, gunfire and artillery exchanges erupted at a crossing point, with state news agency SANA saying “terrorist groups” targeted the area “in an attempt to hinder the humanitarian pause.”

But by afternoon, the clashes had subsided and the east was calm, though the streets were empty.

The truce was initially described as lasting just 11 hours, but Russia’s Defense Minister Sergei Shoigu announced Thursday afternoon it would be extended.

“A decision was made to extend the ‘humanitarian pause’ by 24 hours,” he said in a statement, leaving unclear exactly when the truce was now scheduled to end.

Thursday, regime troops were calling through loudspeakers for civilians to “seize the chance” and leave.

Russia announced the cease-fire earlier this week, amid growing international pressure over its support for Syrian President Bashar Assad’s campaign to recapture the city.

Russia says the pause is a “goodwill gesture” but rebel groups have said they will not abandon their posts and many civilians fear falling into the hands of the regime forces that surround Aleppo.

More than 250,000 civilians have been trapped in the rebel-held east of the city under near-continuous siege since mid-July.

The Syrian army has said it is opening eight corridors for civilians to leave, two of which can also be used by rebel fighters provided they leave behind their weapons.

The Russian Defense Ministry was streaming live video from several of the corridors, showing ambulances and buses along empty roads.

An AFP photographer in government-held west Aleppo said eight injured people had crossed via the Bustan al-Qasr crossing.

But AFP correspondents in the east visited four crossing points and saw no movement through them.

Some civilians interviewed by AFP said they were eager to leave but wanted more reassurances. “I don’t want to risk my life or my family’s by being among the first to leave,” said Mohammad Shayah, an unemployed father of four.

The U.N.’s humanitarian taskforce chief Jan Egeland said Thursday that Russia, the Syrian government and rebels had given permission for medical evacuations from Aleppo to start Friday.

“We hope that the first medical evacuations can take place tomorrow,” he said, adding that the U.N. hoped to also deliver food to the besieged east.

NATO chief Jens Stoltenberg expressed concern Thursday that a Russian aircraft carrier battle group could join attacks on Aleppo.

Warships from Britain were shadowing the battle group through the North Sea and Stoltenberg said NATO navies would closely monitor the warships in “a responsible and measured” way as it headed to the Mediterranean.

In Brussels, EU leaders were weighing sanctions against supporters of Assad’s regime, according to a draft summit statement obtained by AFP.

EU President Donald Tusk said the organization should keep all options open in dealing with Russia, “including sanctions,” if it continues its “crimes” in Aleppo.

In other developments, Turkey escalated its offensive against Kurdish fighters in northern Syria, pounding them with airstrikes and artillery.

Turkey’s state-run Anadolu news agency said 200 members of the Kurdish-led forces were killed in Aleppo province by the Turkish bombing and shelling.

A senior commander with the main Syria Kurdish militia confirmed the Turkish attack on his forces north of Aleppo but disputed the casualty toll, saying that no more than 10 fighters were killed.

In response, the Syrian military said that it would bring down any Turkish war planes entering its air space.

“Any attempt to once again breach Syrian airspace by Turkish war planes will be dealt with and they will be brought down by all means available,” the Syrian army general command said in a statement.