All South Koreans remaining in Afghanistan must leave the country by no later than July or face criminal punishment, a foreign ministry official said Monday, as unrest grew in Afghanistan amid the ongoing withdrawal of US and its allies' forces.

Afghanistan is currently banned for travel, along with five other foreign countries, including Iraq, Syria and Somalia. A violation of the travel ban is punishable by up to one-year in prison or a 10 million-won fine ($8,837) under Korean law.

A "very small" number of Koreans are still in the country despite the government's repeated requests for withdrawal, the foreign ministry official said, declining to give details on how many are staying due to safety concerns.

A government delegation, headed by a senior foreign ministry official from Seoul, visited Kabul last week to meet with and persuade them to leave as soon as they can, according to the official.

"Despite our request, a very small number of our citizens remain in the country due to personal reasons and we plan to take necessary steps so as to help them evacuate as soon as they can," the official said.

The official added that the government could file a criminal complaint against those remaining there.

Tension is heightening in the war-torn country as Taliban insurgents are taking control of more territory since the US and its North Atlantic Treaty Organization (NATO) allies began pulling out troops in May.

The withdrawal is part of a February agreement signed last year between the US and the Taliban, which commits the latter to meet its promises to ensure that it will cut ties with all extremist groups like al-Qaeda and doesn't become a base for terrorist plots.

The Joe Biden administration plans to complete the withdrawal by Sept. 11, the 20th anniversary of the terrorist attacks on the US. (Yonhap)