US Secretary of State Anthony Blinken urged US allies Monday to take back their citizens detained abroad who fought with Daesh, saying they could not be held indefinitely in Syria.

Blinken made the appeal from Rome during a meeting of the 83-nation anti-IS coalition aimed at defeating the extremist group, calling on the Italian side to focus more on the threat posed by miitants in Africa.

There are 10,000 fighters suspected of being in the ranks of Daesh, who are detained in northern Syria by Kurdish factions allied with Western countries, according to US estimates.

"This situation is intolerable and cannot continue indefinitely," Blinken stressed.

"The United States continues to urge countries, even those participating in the coalition, to take back, rehabilitate, and even prosecute their citizens," he added.

France and Britain, two of the closest allies of the United States, were among the most reticent about returning their citizens, despite repeated calls by the US administration, even during the previous administration headed by Donald Trump.

The two countries that have witnessed bloody terrorist attacks are reluctant to return citizens who have taken the path of extremism to their lands.

Blinken praised Italy as one of the few European countries to take back these fighters. He also welcomed the efforts made by Central Asian countries such as Kazakhstan, which, he said, have returned 600 fighters and their family members and approved rehabilitation programs for them.

A Human Rights Watch report published in March said that the Syrian Democratic Forces, an Arab-Kurdish alliance in northern Syria, is holding more than 63,000 women and children, family members of suspected Daesh fighters from more than 60 countries, in two camps surrounded by barbed wire.

Blinken noted that the United States will allocate $436 million in aid to provide housing for Syrians in the camps and for COVID vaccination efforts.

- Strengthening efforts in Africa -

Daesh lost nearly all of the territory it held in Syria and Iraq, where it established a "caliphate" at one point marked by brutal campaigns against religious minorities and women.

But the influence of extremists is increasing in Africa, especially in the Sahel region, where France decided to end its military campaign, and in Mozambique.

Italian Foreign Minister Luigi Di Maio called for the formation of a new working group to confront "the growing threat of the Islamic State in Africa."

Blinken pointed out that the coalition is focused on cutting funding to extremists in Africa and mentioned that two African countries, the Central African Republic and Mauritania, joined the coalition during the Rome meeting.

He also announced that the United States would include Osman Eliaso Djibo, a leader of Daesh who was born in Niger and currently lives in Mali, on its list of "terrorists", which means that any financial dealings with him will be considered a crime under American law.

The Rome meeting is the first in-person meeting held by the ministers of the coalition countries since February 2019, as the Corona virus cast a shadow over international diplomacy.

The coalition was shaken by Trump's sudden decision to withdraw his country's forces from Syria, declaring that the United States had completed its mission there.

Trump eventually left a small force, in a move supported by current President Joe Biden, in part to prevent Turkey from carrying out a new military operation against Kurdish forces it accuses of being linked to the outlawed Kurdistan Workers' Party (PKK).