N"DJAMENA, Aug 5 (Reuters) - At least 26 Chadian soldiers were killed in the early hours of Thursday by suspected Boko Haram assailants following an attack on their patrol around the Lake Chad area, army spokesman General Azem Bermandoa said. A further 14 soldiers were wounded in the encounter, which ended with the army repulsing the attackers, Bermandoa said. Chad is a key contributor to a multinational force in the Lake Chad basin fighting jihadist insurgency Boko Haram, which erupted in northeast Nigeria in 2009. It has since killed more than 30,000 people and forced about 2 million to flee their homes.