There has been no word from Keita since Tuesday, when he dissolved parliament and then resigned after being detained at gunpoint, deepening the crisis facing a country struggling to fend off an insurgency by Islamist militants.

The human rights team was given access to Keita and other detainees, the U.N. peacekeeping mission, known as MINUSMA, said on Twitter. It provided no details on what was said or on the condition of the captives.

The streets of the capital Bamako were calm for the third straight day on Friday ahead of a mass rally planned by an opposition coalition that led protests against Keita before the coup and has since embraced the mutineers.

Junta leaders have promised to oversee a transition to elections within a “reasonable” amount of time. But the military overthrow has dismayed international and regional powers, who fear it could further destabilise the former French colony and West Africa’s entire Sahel region.

A coup in 2012 helped hasten a takeover of northern Mali by al Qaeda-linked militants, and al Qaeda and Islamic State affiliates are active in the north and centre of the country.

A delegation from the 15-nation Economic Community of West African States (ECOWAS) is expected to arrive soon in Bamako, after the bloc held an emergency summit on Thursday aimed at reversing the coup.

The mission, led by former Nigerian President Goodluck Jonathan, intends “to negotiate the immediate release of the president and also ensure the restoration of constitutional government,” Jonathan’s spokesman said, adding that the timing of the visit is not yet confirmed.

ECOWAS has already suspended Mali’s membership, shut off borders and halted financial flows to the country.