Several hostages, including some foreigners, captured by Islamist gunmen during a Mali hotel siege are thought to have been freed following an operation by Malian forces against the militants, AFP reported citing security sources.

"We cannot say that everything is finished, but a number of hostages have been freed," said a security source. The nationalities of the freed hostages are yet to be ascertained and their release has not been independently verified.

It is also not known how many people are still being held by the captors.

A Russian citizen and a Ukrainian are believed to be among the hostages, their respective embassies said in a statement.

"In addition, three citizens of South Africa and a French citizen may be held hostage," the Ukrainian foreign ministry statement added.

Gunmen attacked the Byblos Hotel in Mali's central town of Sevare resulting in the killing of at least seven people, including two gunmen. Malian soldiers were also among the dead. The hotel is popular and frequented by UN peacekeeping personnel.

Some of the UN peacekeepers were at the hotel when the siege was launched.

The UN peacekeeping mission in Mali, Minusma, condemned the attack saying: "The attackers, who were repulsed by the Malian forces, then holed up in a hotel. The clashes between the attackers and Malian security forces continued throughout the morning and sporadic fire continues at the hotel and in the neighbourhood."

The siege took place on Friday, 7 August, when a group of unidentified gunmen stormed the hotel, about 600kms from Malian capital Bamako.

The former French colony has been reeling under intense violence mostly due to al-Qaeda-inspired Islamist groups in the northern parts of the country. France waded into the conflict in January 2013 to stop the advancing militia in the southern region.