Crawford (Texas), Jan. 2 (Reuters): President George W. Bush ordered the US flag to be flown at half mast for five days to honour victims of the Indian Ocean tsunami as a White House delegation prepared to visit devastated areas.

A day after he raised the US tsunami aid contribution 10-fold to $350 million amid pressure from critics, Bush used his weekly radio address to emphasise the need for private relief donations to the region.

?The carnage is of a scale that defies comprehension,? said Bush.

In a White House proclamation issued in Crawford, Texas, where Bush is vacationing on his ranch, the President ordered the flag to be flown at half staff from Monday to Friday next week at all US public facilities and military installations, including embassies and naval vessels.