GAZA — Gaza’s third marathon run, an annual fund-raising event planned for April 10, was canceled after the Palestinian territory’s Islamic leaders barred women from participating, the organizer, the United Nations Relief and Works Agency said on Tuesday.

The ban is the latest in a series of decisions by Hamas, which governs here, seeking to enforce tougher Islamic strictures on an already conservative society. But some of the measures have been unpopular, and enforcement has ebbed and flowed.

Adnan Abu Hasna, a spokesman for the United Nations agency, said the marathon was canceled after Hamas informed the agency that women would not be allowed to take part under any circumstances. Of the more than 2,400 people registered for the race, some 370 were women, nearly two-thirds of them Gazans. Hamas had no objection to the participation of girls among the 1,600 schoolchildren set to run.

In a statement, the agency called the development “disappointing.” It said runners who intended to come from outside Gaza to race were still welcome to visit the coastal enclave, and that alternative activities were being studied.