Sentence:  But they refuse , as do the Arab states , to support the United Nations ' expenses of <WSD>maintaining</WSD> the United Nations Emergency Force in the Middle East as a buffer between Egypt and Israel , and the U. N. troops in the Congo , which expenses are not covered by the regular budget of the United Nations , but by a special budget . 
Meaning of the word marked with <WSD> tags:  keep in a certain state, position, or activity; e.g., "keep clean"