CNN's Frederik Pleitgen, who has traveled to and covered Syria for years, was recently in Aleppo on a trip facilitated but not coordinated by the Syrian military.

Aleppo, Syria (CNN) Years of combat have turned Aleppo's old town into a neighborhood of rubble and dust.

What's left of this once-beguiling maze of narrow alleys and covered souks is a reminder of its tragic location at the heart of Syria's five-year civil war.

U.N. struggles to get food to starving Syrians

U.N. struggles to get food to starving Syrians 02:29

U.N. struggles to get food to starving Syrians

The city's once-famous Khan al-Wazir inn lies completely burned out; as we walked through one of its halls, eerie beams of light shone in through the broken windows.

On the streets nearby, we glimpsed movement inside buildings that looked, at first glance, to be nothing more than abandoned ruins, revealing that people are still living amid the wreckage.

Aleppo is on the demarcation line between the military forces of Syrian President Bashar al-Assad and opposition fighters who have been struggling for years to take his government down.

We had a rare opportunity to reach Aleppo and were accompanied by Syrian troops, giving us a chance to hear directly from a commander on the ground.

Bullet holes puncture street signs meant to help tourists find their way around Aleppo's old town.

His view was that Assad's troops believe they are on the verge of a decisive victory.

He said they are dealing a crushing blow to the opposition -- one that could drastically alter the momentum of this protracted conflict.

Commander: Regime morale high

The commander loyal to Assad told us he can't remember a time when morale has been better. He asked that CNN not use his real name, but instead call him Abu Mohammed.

"Things have changed drastically," he said. "The insurgents are running away to Turkey. Running from the wrath of the Syrians and our allied troops."

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The opposition rebels say they are simply being slaughtered by the Russian air force, Iranian militias and the Syrian military.

Russian firepower

Assad's forces are grateful for the assistance they say has turned the course of the war in their favor: Russian air power.

The Russian military has been helping Assad's forces, going after a coalition of rebels in the eastern part of the city.

"It is only a matter of months till we win, thanks to the Russian support with their airstrikes flown from the Syrian airfield, which will defeat the rebels once and for all," Abu Mohammed said.

The roar of planes overhead is loud and constant. Rattling thuds shake the ground -- the sounds of bombs exploding nearby.

"The rebels are only a few yards away," a sniper told us, explaining that the Syrian military continues to engage in close-quarter firefights with the rebels.

"They often try to sneak up on us but we detect them and they fail."

A gun and teacups sit amid the rubble in a fighting position held by Syrian regime forces.

Abu Mohammed, the commander, warned the U.S. not to interfere: "We are steadfast," he insisted.

"You cannot defeat the Syrian army because we are determined to win and we are loyal to President Assad."

No respite for war-weary

But the new offensive has done little to ease the plight of Aleppo's war-weary residents.

It has prompted tens of thousands of people to flee toward the Turkish border; others remain all but trapped in the rebel-held part of Aleppo.

The International Committee of the Red Cross estimates that about 50,000 people have been displaced by the fighting. Some of the supply routes used for delivering aid have been cut, the organization said in a statement.

Photos: Syrian refugees flee embattled city of Aleppo Syrian refugees await their fate near the Turkish border gate as they flee the northern embattled city of Aleppo on February 6, 2016. Hide Caption 1 of 17 Photos: Syrian refugees flee embattled city of Aleppo Refugees push each other as they wait for tents near the Turkish border on February 6. Hide Caption 2 of 17 Photos: Syrian refugees flee embattled city of Aleppo A refugee girl reacts near the Turkish border gate on February 6. Hide Caption 3 of 17 Photos: Syrian refugees flee embattled city of Aleppo Refugees jostle one another for tents near the Turkish border on February 6. Hide Caption 4 of 17 Photos: Syrian refugees flee embattled city of Aleppo Refugee children arrive at the Turkish border gate on February 6. Hide Caption 5 of 17 Photos: Syrian refugees flee embattled city of Aleppo Syrian refugees are pictured in a camp as they flee the city of Aleppo on February 6. Hide Caption 6 of 17 Photos: Syrian refugees flee embattled city of Aleppo A refugee carries a heavy bag of items near the Turkish border gate on February 6. Hide Caption 7 of 17 Photos: Syrian refugees flee embattled city of Aleppo A refugee woman carries her belongings near the Turkish border gate on February 6. Hide Caption 8 of 17 Photos: Syrian refugees flee embattled city of Aleppo Refugee children sit on a car near the Turkish border crossing on February 6. Hide Caption 9 of 17 Photos: Syrian refugees flee embattled city of Aleppo A refugee warms himself at a bonfire near the Turkish border on February 6. Hide Caption 10 of 17 Photos: Syrian refugees flee embattled city of Aleppo Refugees brave the cold and rain as they arrive at the Turkish border on February 6. Hide Caption 11 of 17 Photos: Syrian refugees flee embattled city of Aleppo A child tries to climb over a fence near the Turkish border as Syrians fleeing the northern city of Aleppo wait on February 6. Hide Caption 12 of 17 Photos: Syrian refugees flee embattled city of Aleppo A young refugee carrying belongings arrives at the Turkish border on February 6. Hide Caption 13 of 17 Photos: Syrian refugees flee embattled city of Aleppo Refugees arrive near the Turkish border as they flee the city of Aleppo on February 6. Hide Caption 14 of 17 Photos: Syrian refugees flee embattled city of Aleppo A child carries his belongings as Syrian refugees arrive at the Turkish border on February 6. Hide Caption 15 of 17 Photos: Syrian refugees flee embattled city of Aleppo A child sleeps as Syrians fleeing the northern embattled city of Aleppo wait near the Turkish border on February 5, 2016. Hide Caption 16 of 17 Photos: Syrian refugees flee embattled city of Aleppo A Syrian teenager and a child look on near the Turkish border on February 5. Hide Caption 17 of 17

"The fighting is putting enormous pressure on civilians," said Marianne Gasser, the head of the ICRC delegation to Syria, who is in Aleppo.

"The temperatures are extremely low and, without an adequate supply of food, water and shelter, displaced people are trying to survive in very precarious conditions."

Water supplies in the city have been cut and residents are having to rely on the Red Cross for water. There are also shortages of fuel and electricity, Gasser said.

Aleppo's citadel is visible from a Syrian government position.

On the front line, the Syrian military remains confident.

The Syrian government has made major gains around Aleppo and has all but surrounded the various rebel groups, including fighters from al Nusra Front, the al Qaeda affiliate in Syria.