French and Malian troops were due to sweep the outskirts of towns recently recaptured from the al Qaeda-linked rebels for landmines they suspect the extremists left as they fled an air and ground assault by the armies.
Nearly two weeks after the UN-backed offensive was launched in Mali to dislodge the Islamists, the deteriotating situation prompted Japan to shut its embassy and evacuate key staff.
"After the French military advance the already unstable situation in Mali worsened further," foreign ministry spokesman Yutaka Yokoi told reporters in Tokyo.
The decision came a day after Japan announced that at least seven of its citizens were killed in a hostage siege in Algeria, which neighbours Mali, after an attack by Islamists which they said was retaliation for the French offensive.
France swept to the aid of the ill-equipped Malian army on January 11, as the extremists which seized the vast north in April 2012 made a push south towards the capital Bamako.
The former colonial power has said it could deploy upwards of 2,500 troops which would eventually hand over control to a West African force of over 4,000 troops which will be boosted by 2,000 men pledged by Chad.
UN chief Ban Ki-moon hailed France's "courageous" intervention but expressed fears over the safety of humanitarian workers and UN employees on the ground.
He added the proposed African force in Mali needed "critical logistical support" to help it take over from French forces.
The fallout from the war, which experts have warned could be drawn out and complex, is causing concerns.
The UN refugee agency estimates up to a million people could have fled their homes in coming months, and rights bodies have warned of the dire situation faced by those escaping fighting.
There are also increasing reports of attacks on light-skinned Tuareg or Arabs from Malian security forces.
"Here if you wear a turban, have a beard and wear a Tuareg robe, you are threatened," said a shopowner in Segou, a town some 270 kilometres northeast of Bamako.
"It has become very dangerous for us since this war started."
Afraid of being targeted, his son has shaved his beard and stopped wearing his turban, traditionally sported by Tuaregs and Arabs who make up the bulk of the armed rebel groups.
Malian army chief General Ibrahima Dahirou Dembele promised that any soldier involved in abuses would be brought to book.
"One mustn't get confused. Every white skin is not a terrorist or a jihadist and among the enemy which attacked our different position were many black skins. We are among brothers, whether one is black or white."
Meanwhile international moves to aid the operations revved up with the US military airlifting French troops and equipment from France into Mali.
"We expect the mission to last for the next several days," an AFRICOM spokesman, Chuck Prichard, told AFP in Germany on Tuesday.
Italy, Belgium, Britain, Canada, Denmark, the Netherlands, Spain and the United Arab Emirates are also providing transport planes or helicopters required to help move the African and French troops around Mali's vast expanses.
Mali's year-long crisis began when Tuaregs returning from fighting Kadhafi's war in Libya, battle-hardened and with a massive arsenal, took up a decades-old rebellion for independence of the north which they call Azawad.
They allied with hardline Islamists amid a political vacuum in Bamako after a March coup, and seized the key towns of Kidal, Gao and Timbuktu in a matter of days.
The Islamists later broke with their Tuareg allies, and with firm control of the north, implemented brutal sharia law.
The occupation sparked fears abroad that the vast northern half of the country could become a new Afghanistan-like haven for al-Qaeda, prompting France to step as UN-backed plans for a regional intervention remained mired in hesitation.
French fighter jets have pounded Islamist strongholds in Gao, Kidal and Timbuktu, the fabled city where they destroyed a mansion belonging to slain Libyan leader Moamer Kadhafi which served as a key base for the north African al-Qaeda branch.
Mali's army chief has said his French-backed forces could reclaim the northern towns of Gao and Timbuktu in a month.