Malian security forces have arrested four suspects accused of kidnapping two French nationals last month on behalf of al-Qaeda's North African wing, the West African state said.
The Mali national broadcaster ORTM showed pictures of three of the four arrested men on Monday.
The West African state is under growing international pressure to step up the fight against al-Qaeda in the Islamic Maghreb (AQIM), which has been held responsible for a series of kidnappings of Westerners in the Sahel region.
A spokesperson for the Malian presidency said the four suspects are "subcontractors for AQIM, to whom they handed over the hostages".
The two French citizens, described by Malian officials as an engineer and a technician who work for a local cement firm, were kidnapped on the night of November 23 in the town of Hombori, about 200km west of the northern city of Gao.
AQIM last week claimed responsibility for the kidnapping of the two French citizens, whom it described as French spies, and three other Westerners from an undisclosed European country in a separate incident in the north of Mali a few days later.
On Tuesday, following the arrests, AQIM reportedly posted images of the five Europeans on an Islamist website. In two photographs the hostages are surrounded by masked men holding guns, the Reuters news agency reported.
The spokesperson said the suspects are all Malian nationals from the north of the country. Mali said earlier this month it believed the hostages were alive and it was trying to free them.
Governments in the Sahel region including Mauritania, Algeria, Mali and Niger are struggling to contain the growing threat by Islamic armed groups in the region, which has long been a safe haven for rebels and smugglers.
Alain Juppe, the French foreign minister, said on Sunday that security concerns for the Sahel had risen since the Libyan war and said Mali was not doing enough in regional efforts.
A group that was once part of AQIM has broken away from the movement to form a splinter group, the AFP news agency reported.
Two Spanish men and an Italian woman kidnapped in Algeria in October and purportedly held by new group were seen alive in a video shown to an AFP correspondent on Monday.
The undated footage shows the hostages' faces clearly and is preceded by the name of the previously unknown organisation that claimed their abduction on Saturday, Jamat Tawhid Wal Jihad Fi Garbi Afriqqiya (Unity Movement for Jihad in West Africa).
The hostages can be heard identifying themselves in their own languages. The man's foot is bandaged and the two women are clad in blue gowns and yellow headscarves.
In the background, masked gunmen can be seen keeping watch.
"This is the Jamat Tawhid Wal Jihad Fi Garbi Afriqqiya in west Africa. We claim the operation carried out on October 23 at Tindouf when two Spaniards and an Italian were kidnapped," the message sent to AFP said.