The investigation into the November 20 attack on the Radisson Blu in Bamako which left 20 people dead is being carried out by Malian investigators as well as experts from the United Nations, France, Canada and Belgium.
"There are some avenues available, but at the moment, the inquiry is at a standstill," a Malian security source said, speaking on condition of anonymity.
Foreign experts do not work "in the same manner" as their Malian colleagues, and resuming the probe will require "changing working procedures", she said without elaborating.
The UN source declined to give details.
A Malian investigator, who also did not want to be named, said there had been "a divergence" over the surveillance of possible suspects currently at large.
The November siege left 20 people dead, including 14 foreigners, after gunmen took guests and staff hostage, security sources said.
Al-Murabitoun group, an Al-Qaeda affiliate led by one-eyed Algerian militant Mokhtar Belmokhtar, claimed it was behind the deadly raid.
Another jihadist group from central Mali, the Macina Liberation Front, later also claimed responsibility.
Sources close to the inquiry said two other suspects were "actively" wanted.
A Malian investigator, meanwhile, said officials were also awaiting results from an American inquiry regarding the weapons used by the attackers and their DNA.
