The United Nations plans to expand its humanitarian aid deliveries to Syria's opposition-held northwest to help millions of people affected by the Feb. 6 earthquakes, which devastated the region, a senior official said on Thursday.

But Muhannad Hadi, the global body's Regional Humanitarian Coordinator (RHC) for the Syria Crisis said the planned increase in aid trucks to 40 per day was still inadequate for tackling the region's humanitarian crisis, with medical supplies to combat disease, as well as more food and temporary shelters, urgently needed.

More than 280 trucks have crossed the Turkish border into northwestern Syria since aid operations resumed on Feb. 9, three days after the quake, following a break caused by highway damage, Hadi told Reuters.

The northwest, which is controlled by opposition groups at war with Syrian President Bashar Assad and where 90% of the 4 million-plus population were already depending on aid to meet basic needs, was the worst hit in Syria.

The disaster killed more than 4,500 people there, according to the United Nations.

"We are hoping very soon this week to have 40 trucks delivering aid a day which is double of what we used to bring in before the earthquake as more resources become available," Hadi said.

The increase in aid is linked to the opening of additional crossings from Türkiye into opposition-held Syria: Among them is Bab al-Hawa, already in use under U.N. Security Council authorization. Assad has given exceptional clearance for two others to be opened for three months.

Bashar Assad regime officials have also granted a blanket authorization – rather than case-by-case approvals – for the same period for cross-line deliveries from government-controlled areas into the northwest.

But the U.N. and other aid groups say hardline forces there have blocked such deliveries while other relief bodies complain of security restrictions by the Bashar Assad regime that they say politicize aid distribution.

Flows of urgently needed aid via these routes will increase further once the U.N. is granted access by all parties, Hadi said.

"We have commodities in the regime-held areas, we have warehouses... and when you have people in need you need to think of efficiency and effectiveness. It's not about politics. We need access from all directions," he said.

The crisis could lead to a resurgence of waterborne diseases linked to widespread infrastructure damage. "After the earthquake, we started coming across suspected cases of cholera and deaths that could be related to cholera," Hadi noted.

While the worst destruction inside Syria was concentrated in the northwest, some 8.8 million had been affected across the country and, on their behalf, donors needed to respond fast to a $400 million funding appeal, he said.

That was on top of another $4.8 billion already needed across Syria for this year.

"If we don't get funding quickly and if we are not able to replenish stocks we will be put in a difficult situation," Hadi said.