The World Health Organization (WHO) has urged governments and civil society to work together to ensure cross-border delivery of humanitarian aid between Türkiye and Syria and within Syria itself.

WHO's Regional Director for Europe Hans Kluge called the earthquakes "the worst natural disaster" in the region in a century, and emphasized the importance of all parties cooperating on aid delivery.

"The needs are huge, increasing by the hour. Some 26 million people across both countries need humanitarian assistance," said Kluge during a press conference on Tuesday.

Türkiye has suffered cataclysmic casualties, Kluge underlined, with more than 31,000 deaths and 100,000 people injured due to the earthquakes. An additional one million people are estimated to have lost their homes, and are currently living in temporary shelters.

Meanwhile, almost 5,000 people have died in northwest Syria across the border, and the death toll is expected to rise.

The WHO also warned that there were growing concerns over health risks related to cold weather, hygiene and sanitation, and the spread of infectious diseases. Meanwhile, with 80,000 people currently hospitalized, the Turkish health system is under enormous strain.

The WHO has launched an appeal for $43 million to help with the earthquake response, and Kluge said this amount was likely to double in the coming days due to the huge scale of need.

According to Kluge, the funds would be used to assist the most vulnerable by providing trauma care, essential medicines, and mental and psychosocial support. The funds would also be used to ensure the continuity of routine health services.

On the same day, the United Nations Secretary-General Antonio Guterres launched an appeal for $397 million to help earthquake victims in Syria, adding that the world body was in the "final stages" of a similar appeal for Türkiye.

Guterres called on member states to "fully fund this effort without delay and help the millions of children, women and men whose lives have been upended by this generational disaster."

(With input from agencies)