COLOMBO, Sept. 28 (Xinhua) -- At least 23 Tamil Tiger rebels were killed while 31 others were injured by government troops in the north, Sri Lankan defense officials said on Sunday.

    The military spokesman Udaya Nanayakkara said the clashes erupted in several places on Saturday in the ongoing humanitarian operation launched by the military to free the Tamil population from clutches of Liberation Tigers of Tamil Eelam (LTTE) rebels.

    The government says the troops are on the verge of capturing the rebel headquarters in the Kilinochchi district, dealing the final blow to the LTTE in the successful military campaign which began in mid-2006.

    Civilians in the rebel controlled areas have been asked by the government to arrive in the government controlled areas as a preparation for the final onslaught.

    The LTTE rebels has been fighting nearly three decades with the troops to set up a separate homeland for the minority Tamils in the Northern an Eastern Provinces.