COLOMBO, March 16 (Xinhua) -- The United Nations' resident humanitarian office in Sri Lanka on Monday blamed Tamil Tiger rebels for forcible recruitment of its staff.

    "It holds grave fears for the safety of one UN national staff member and three dependent family members who were forcibly recruited over the weekend by the LTTE (Liberation Tigers of Tamil Eelam) inside the government declared no fire zone," the office said in a statement.

    The statement added that another of its national staff members recruited two weeks ago has yet to be released.

    The LTTE has come in for wide condemnation for holding civilians as human shields in the current military conflict.

    The rebels have been pushed to an area of around 30 sq km in the north by the advancing military in their bid to completely crush the rebel challenge.

    The government declared no fire zones in order to make the civilians leave the fighting zone. Almost 36,000 people have arrived in government held areas, according to the government.

    Rebels have faced accusations of causing injuries to civilians by firing at them when they tried to flee the LTTE held areas.

    Meanwhile, the government has denied shelling the no fire zone causing injuries to people and rejected calls for a ceasefire made by the international community.

    The LTTE began to rebel against the government to set up a separate homeland for the minority in the north and east in the mid-1980s, based on claims that the minority Tamils were being discriminated by the majority Sinhalese dominated governments.

    More than 70,000 people have died in the conflict since the mid-1980s.