AMMAN/BEIRUT (Reuters) - After a brief respite, bombs are falling heavily on Aleppo, forcing people there to think again about whether it is time to get out of a city at the epicenter of the Syrian war.

An injured woman is carried after an airstrike in the rebel held area of old Aleppo, Syria April 22, 2016. REUTERS/Abdalrhman Ismail

The momentary normalcy brought by a truce is gone. The parks are empty again, the streets deserted at night. Residents count the explosions and the dead across the frontlines of a city divided between the government and rebels.

There may be worse to come. The government says there will be a new attack to take areas of Aleppo under rebel control, a campaign that would likely aim to seal the last route into rebel-held areas. Air strikes on rebel-held areas have resumed.

Determined to keep their last supply route open, rebels have stepped up their bombardment of government-held areas of the city, and of a predominantly Kurdish district controlled by a militia with which they are also at war.

On both sides of the city, the collapse of peace talks in Geneva has been accompanied by talk of new troop mobilizations on the ground. Rumors swirl of new deployments by government forces and their Shi’ite militia allies on the one hand, and by rebels including jihadist Nusra Front on the other.

“People are most terrified of the air strikes,” said Abdul Moneim Juneid, a community worker in an orphanage in rebel-held Aleppo. “People had felt tangibly the benefits of the truce” and yearned for security, he said.

But leaving to Turkey, where hundreds of thousands have fled since the eruption of the conflict in 2011, is no longer an option. The border is closed to most. “What’s on many people’s minds is the border crossing with Turkey,” he said.

“If Turkey had opened the borders, you would have seen the population of Aleppo go down by half.”

All the main combatants in the multi-sided Syrian war are fighting in the Aleppo area: insurgents have been waging separate campaigns with the government, the Syrian Kurdish YPG, and Islamic State near the Turkish border.

Aid agencies have expressed concern about the fate of tens of thousands of Syrians currently trapped at the border with Turkey, already hosting some 2.5 million Syrian refugees.

GETTING OUT

A short drive from the Turkish border, Aleppo was Syria’s biggest city before the conflict, home to more than 2 million people and an engine of the economy.

Today, some 300,000 are estimated to live in rebel-held areas that have sustained heavy casualties and massive destruction as a result of government bombardment that has already forced many to flee.

Backed by the Russian air force and allied militia from Iran and Lebanon’s Hezbollah movement, the government managed to cut the rebels’ most direct supply route into Aleppo in February.

The defeat of the opposition in Aleppo would be a crushing blow to the insurgency, and also a blow to Turkey which has backed the Syrian rebel groups fighting near its frontier.

The government-held side of the city is still home to more than 1 million people. The level of casualties and destruction there has been far lower than in the opposition-held areas.

But growing rebel fire power has exacted a heavier toll than at the start of the war.

After the truce, “life had started to return to the city ... people were out until late at night”, said Soheib Masri a 29-year-old journalist, speaking by phone from the government side. Now, people were moving away from frontline areas again into safer parts of the city, and in some cases leaving altogether.

“There is a new movement of Aleppo residents towards the other provinces, towards the coast,” he said. “I am thinking of getting my family out because there is great fear. The shelling today isn’t like before ... they’ve got rockets that go further.”

The route out of government-held Aleppo is also vulnerable. The main Damascus-Aleppo highway runs through rebel held territory, leaving the government dependent on a circuitous desert road that is vulnerable to Islamic State attack.

That road was cut as recently as February by an Islamic State assault. The group remains poised some 10 km (6 miles) away, according to the Syrian Observatory for Human Rights, a Britain-based monitoring group.

“WE CANNOT MOVE”

Recapturing all Aleppo has been a government priority since the Russian air force intervened in support of Assad last September, tipping the conflict his way.

The “cessation of hostilities” deal brokered by the United States and Russia in February began to unravel in the Aleppo area this month with each side accusing the other of attacking first.

Several U.S. officials said this week that the Russian military had repositioned artillery near Aleppo, adding to speculation of an another assault on the city.

The opposition’s only way in and out of the city is the so-called Castello road, which provides access to Aleppo’s rebel-held western approaches but passes within firing range of Sheikh Maqsoud, an Aleppo district held by the Kurdish YPG militia.

Enmity between the YPG and rebels has spilled into all-out war in the Aleppo area since late last year. Rebels say their attack resulted from YPG attempts to cut the road.

Mohamad Sheikho, a Sheikh Maqsoud resident and member of a leading Kurdish political party, says rebel bombardment has killed 109 people in Sheikh Maqsoud since February. “We cannot move, I tell you. It is besieged,” he said by phone.

“The humanitarian situation is extremely bad.”

The Observatory, which tracks all sides of the conflict, said that while some goods could be smuggled into Sheikh Maqsoud from adjoining government-held districts, it was considered besieged.

Rebels say the YPG wants to take the Castello road in collaboration with Damascus.

“Twenty brigades of the FSA agreed to teach the PKK a lesson,” said Zakaria Malahifji of an Aleppo-based rebel group, referring to the Sheikh Maqsoud attack.

The rebels often call the YPG the PKK, a reference to its links to the Turkish Kurdistan Workers’ Party, which is considered a terrorist group by Turkey, the United States and the European Union. The YPG denies rebel assertions that coordinates its attacks with Damascus.

Some in Aleppo say they will not leave, regardless of how bad it gets.

“We have been living in this state of war for three years. The people have gotten used to it,” said Ammar al-Absi, a member of a rebel-run local council.

Nuha Ftaima, a 52-year-old school teacher living on the government side, says she will never leave.

Both her husband and brother have been killed in the war, one shot by a sniper and the other killed by a shell.

Speaking by phone as an explosion could be heard in the background, she said it was time the Syrian army put an end to the insecurity. “Without prevarication I say it. We call for a military solution,” she said.