United Nations (UN) High Commissioner for Refugees Filippo Grandi said on Monday that he has arrived in Afghan capital Kabul to assess the humanitarian situation and the requirements of displaced Afghans. 

"During my visit I will assess the country's acute humanitarian needs and the situation of 3.5 million displaced Afghans," he tweeted. "I am grateful to all UN, NGO and other humanitarian workers who are working hard on the ground to meet those needs."

The UN refugee agency has previously warned that a major humanitarian crisis is looming in Afghanistan after the Taliban took over Kabul and the majority of the country.

The UN is convening an aid conference in Geneva on Monday in an effort to raise more than $600 million for Afghanistan.