Japan was set to evacuate all personnel from its embassy in Kabul, Japanese government sources said Sunday, as Taliban fighters reportedly entered Afghanistan's capital calling for a peaceful transfer of power.

A dozen Japanese staff work at the embassy. The United States evacuated its embassy staff by helicopter amid the political crisis.

"The situation is developing very quickly," one of the sources said. "We are gathering information in cooperation with the United States and European countries."

More than 60 countries, including Japan, issued a joint statement saying Afghans and international citizens who want to leave Afghanistan must be allowed to depart and added that airports and border crossings must remain open, the U.S. State Department said late Sunday.

The U.S. government and countries including Australia, Canada, France, Germany, Italy, South Korea, Qatar and the U.K. said in a joint statement that "those in positions of power and authority across Afghanistan bear responsibility — and accountability — for the protection of human life and property, and for the immediate restoration of security and civil order."

It added that "the Afghan people deserve to live in safety, security and dignity. We in the international community stand ready to assist them."

The Taliban declared the war in Afghanistan was over after insurgents took control of the presidential palace in Kabul as U.S.-led forces departed and Western nations scrambled on Monday to evacuate thousands of their citizens.

American diplomats were evacuated Sunday from their embassy by chopper after a lightning advance by the militants, who were poised to run Afghanistan again 20 years after they were toppled by U.S.-led forces following the Sept. 11 attacks on the United States.