"The anti-terrorist struggle in the Sahel requires determination, endurance and humility. We are faced with a hard fight," Edouard Philippe told reporters.
The prime minister arrived late Friday in the capital Bamako along with Defence Minister Florence Parly, on a visit to show "support" for Mali, where some 4,500 French troops have been deployed since 2014 to retake the north of the country after it fell to jihadist fighters.
"We see that we are achieving results, we disrupt networks, I have no doubt that this presence has an impact", he said.
The French military "will remain as long as is necessary".
But he declined to comment in detail on the death in Mali on Thursday of Djamel Okacha, an Algerian commander for Al-Qaeda in the Islamic Maghreb (AQIM).
Mali's government said Friday that French armed forces killed Okacha in an air and ground ambush on a column of vehicles he was travelling in north of Timbuktu.
His death ended a years-long hunt for a man accused of masterminding the kidnapping of Westerners in the Sahel region.
Okacha, a jihadist veteran known also as Yahya Abou El Hamame, was believed to be second in command of the Group to Support Islam and Muslims (GSIM), also known as Nusrat al-Islam.
The group was formed by the merger of Ansar Dine, the Macina Liberation Front, Al-Mourabitoun and El Hamame's Sahel branch of AQIM.
In addition to French troops in Mali, around 15,000 peacekeepers have been deployed in the country as part of the United Nations stabilisation mission known as MINUSMA.
This followed the signing of a peace accord in 2015 between the Bamako government and armed groups.
But jihadist groups have continued operating in Mali and neighbouring countries.
Supported by France, Burkina Faso, Chad, Mali, Mauritania and Niger have formed the so-called G5 Sahel group to fight the jihadists.
During his two-day visit Philippe is to hold talks with his Malian counterpart Soumeylou Boubeye Maiga and President Ibrahim Boubakar Keita.
He is to sign development accords with Mali worth 85 million euros ($96 million), including 50 million in loans and 35 million in grants via the French Development Agency.
Published : February 23, 2019
By : Agence France-Presse Bamako