New Delhi, March 18 -- Haiti has a chance now to tackle pervasive gang violence with a U.S.-initiated international force starting to deploy and a prime minister committed to providing alternatives for young gang members, the United Nations' expert on human rights in Haiti said Monday.

"We're in a place now where the next few months are going to be crucial," said William O'Neill, who visited Haiti this month. "And I think it can turn around, because the gangs, at the end of the day, are not that powerful."

The U.N. Security Council on Sept. 30 approved a plan co-sponsored by the U.S. and Panama to authorize a much larger, 5,550-member force with expanded powers to help stop the escalating gang violence in Haiti. It is aimed at transform...