JOHANNESBURG, Oct 5 (Reuters) - Southern African regional bloc SADC agreed at a summit on Tuesday to extend a troop deployment in Mozambique to help the government fight an Islamic State-linked insurgency. "Summit approved the extension of the SAMIM (SADC Mission in Mozambique) to continue with offensive operations against terrorists and violent extremists," the bloc said in a communique after top officials met in Pretoria, South Africa. The SADC troop deployment was initially for three months and due to end on Oct. 15. The communique did not say how long the extension was approved for. Southern African nations agreed in June to send troops to help Mozambique respond to the insurgency, which is concentrated in the northern province of Cabo Delgado and has claimed thousands of lives since beginning in 2017. read more Rwanda, which is not a SADC member, began deploying soldiers in Mozambique a month later. read more The fighting brought a $20 billion natural gas project led by French energy company TotalEnergies (TTEF.PA) to a halt, after fighters attacked the town of Palma in March. read more The communique on Tuesday said three soldiers on the SADC mission to Mozambique had lost their lives, from Botswana and Tanzania.