Bamako - French and UN investigators joined a Mali police probe into a jihadist siege at a luxury hotel that left at least 20 dead, as flags were lowered on Monday for three days of mourning.
Security was tightened at hotels in the capital, Bamako, while neighbouring nations Senegal, Mauritania and Guinea joined in the three days of mourning over Friday's bloodshed.
Benin's president Thomas Yayi Boni said after visiting the Radisson Blu hotel, where the killings took place, that the "odious attack" was aimed at "frightening off international investors".
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The assault began on Friday morning when gunmen went on the rampage at the hotel, shooting in the corridors and taking 170 guests and staff hostage before Malian and international troops stormed the building.
Prosecutor Boubacar Sidiki Samake, who is in charge of the anti-terrorist probe, said late on Monday that the toll had climbed from 19 to 20 dead, with nine people injured.
The two gunmen were also killed in the attack, he said on Malian public television.
Suitcase with grenades
The UN peacekeeping force in Mali (MINUSMA), which is helping with the inquiry, gave the same toll.
The hotel was popular with businessmen, diplomats and other expatriates and many foreigners were among those killed, including six Russians, three Chinese, two Belgians, an American, an Israeli and a Senegalese national.
The attack has been claimed by two separate jihadist groups and investigators are searching for possible accomplices.
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Samake said the investigation was advancing.
"It is clear that they had accomplices who helped them come to the hotel," he said about the gunmen, adding that police had staged several raids on homes.
The police found a suitcase with grenades in the hotel lobby and were following up "several leads" linked to "objects" left by the gunmen, a Malian police source told AFP.
'Gunmen spoke English'
The Al-Murabitoun group, an al-Qaeda affiliate led by notorious one-eyed Algerian militant Mokhtar Belmokhtar, has claimed responsibility for the attack.
The group said on Sunday there were only two attackers and suggested they were Malian.
In a recording broadcast by Al-Jazeera, a spokesperson identified them as Abdelhakim al-Ansari and Moez al-Ansari, the term "al-Ansari" indicating they were indigenous jihadists.
But a jihadist group from central Mali, the Macina Liberation Front (LWF), also claimed the attack in a statement sent to AFP Sunday, saying it was carried out by a squad of five, including "three who came out safe and sound".
Guinean singer Sekouba Bambino Diabate, who was among the survivors, told AFP the gunmen spoke English among themselves.
On Monday, national TV released photos of two dead men said to be the attackers, along with a telephone number to call to offer information.
French Defence Minister Jean-Yves Le Drian has said Belmokhtar, one of the world's most wanted men, was "likely" the brains behind the assault.
French forensic specialists have arrived in Bamako to help with the identification of the victims.
State of emergency
Despite a state of emergency imposed late on Friday, residents of Bamako were trying to return to normal life.
Security remained high at the major hotels and was tighter than usual, though more discreet, at public buildings and banks.
"People are not being vigilant. We forget. I don't know whether it's because of the problems of daily life, but people just aren't being careful here," said hotel worker Daouda Sissoko.
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Others are concerned that Friday's attack will have more economic repercussions for a country still recovering from a 2012-13 civil war.
Mali has been torn apart by unrest since the north fell under the control of jihadist groups linked to al-Qaeda in 2012.
The Islamists were largely ousted by a French-led military operation launched the following year, but large swathes of Mali remain lawless.
France has more than 1 000 troops in its former colony, a key battleground of the Barkhane counter-terror mission spanning five countries in Africa's restive Sahel region.