BEIRUT/GENEVA (Reuters) - Aid trucks reached Syria’s eastern Ghouta region on Monday for the first time since the start of one of the war’s deadliest assaults, but the government stripped some medical supplies from the convoy and pressed on with its air and ground assault.

The convoy of more than 40 trucks pulled out of Douma in darkness after shelling on the town, without fully unloading supplies during a nine-hour stay. All staff were safe and heading back to the capital Damascus, aid officials said.

The Russian-backed Syrian army has captured more than a third of the eastern Ghouta in recent days, threatening to slice the last major rebel-held area near Damascus in two, despite Western accusations it has violated a ceasefire.

The United Nations says 400,000 people are trapped inside the besieged enclave, and were already running out of food and medical supplies before the assault began with intense air strikes two weeks ago.

“The team is safe, but given the security situation a decision was taken to go back for now. They off-loaded as much as possible given the current situation on the ground,” spokeswoman Iolanda Jaquemet of the International Committee of the Red Cross (ICRC) said in Geneva.

Another aid source told Reuters that 10 trucks left the town “fully sealed”, while four more had been partially unloaded.

Hours earlier, a senior U.N. official accompanying the convoy said he was “not happy” to hear loud shelling near the crossing point into eastern Ghouta despite an agreement that the aid would be delivered in safety.

“We need to be assured that we will be able to deliver the humanitarian assistance under good conditions,” Ali al-Za’tari told Reuters at the crossing point.

A World Health Organization official said the government had ordered 70 percent of medical supplies to be stripped out of the convoy, preventing trauma kits, surgical kits, insulin and other vital material from reaching the area. The ICRC confirmed some medical equipment had been blocked but gave no details.

The British-based Syrian Observatory for Human Rights said strikes targeted frontlines near the town of Harasta and the villages of Beit Sawa and Hosh al-Ashari. The monitor later said 80 were killed and more than 300 wounded in the highest toll in one day since the U.N. Security Council resolution was adopted 10 days ago.

A military media unit run by the government’s ally Hezbollah reported that the Syrian army had taken the village of al-Mohammadiyeh, located on the southeastern corner of the enclave.

President Bashar al-Assad said on Sunday his forces would continue the push into eastern Ghouta, a densely populated area of farmland and towns just outside Damascus which government forces have encircled since 2013.

Many civilian residents have fled from the frontlines into the town of Douma.

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Assad and his allies regard the rebel groups that hold eastern Ghouta as terrorists, and say a U.N. Security Council resolution demanding a country-wide ceasefire does not apply to operations against them.

A week ago Russia unilaterally announced five-hour daily pauses in the fighting, but clashes have continued during those hours and Western countries dismissed it as inadequate.

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PATTERN

The fighting in eastern Ghouta follows a pattern used in other areas recaptured by the government since Russia entered the war on Assad’s side in 2015, with sieges, bombardment and ground offensives combined with an offer to let civilians and fighters who surrender escape through “humanitarian corridors”.

For the rebels fighting to oust Assad, the loss of eastern Ghouta would mark their heaviest defeat since the battle of Aleppo in late 2016 and end their ability to target the capital. Rebel shelling on Damascus has killed dozens of people during the last two weeks, state-run media has said.

The Observatory said government forces had captured a third of the area in their advance from the east. Syrian state television on Monday said the army had made major advances, seizing 40 percent of the area previously held by the rebels.

It broadcast live from several captured villages, showing collapsed concrete buildings, rubble-strewn streets, bullet-pocked walls and smoke rising above fields in the distance.

Monday’s convoy carrying aid was the first to reach the besieged area since Feb. 14 and only the second since the start of 2018.

Za’tari said the shipment had been scaled back from providing food for 70,000 people to providing for 27,500. The United Nations says Syria has agreed to allow in the rest of the food for the full 70,000 in a second convoy in three days.

Marwa Awad, spokeswoman for the U.N.’s World Food Program, said it had delivered supplies from the trucks after meeting local councils, including food and nutritional assistance.

The two-week assault has brought footage of children being carried out of rubble and hospitals being bombed to viewers around the world once again. Since the fall of Aleppo more than a year ago, government forces had focused their efforts mainly on Islamic State-held territory in the more remote east of the country, but they have now renewed their campaign to crush anti-Assad rebels in the heavily-populated west.

Moscow and Damascus deny they are killing large numbers of civilians. Assad has dismissed Western statements about the humanitarian situation in eastern Ghouta as “a ridiculous lie”.