Gates, meeting with his counterparts in India, said he signed deployment papers to send a port-clearing ship equipped with cranes to get the port, ravaged by the 7-magnitude earthquake Jan. 12, operating within a week or two to speed up aid distribution, the Pentagon said in a release.
Meanwhile, Port-au-Prince residents were recovering from a strong early-morning aftershock that rocked buildings for several seconds. The U.S. Geological Survey said the revised 5.9-magnitude quake was near the city of Petit-Goave.
A U.N. disaster team in Petit-Goave said there appeared to be little new damage from Wednesday's temblor, The Miami Herald reported. The Jan. 12 earthquake smashed about 30 percent of the city's buildings.
Mike Morton, a member of the U.N. team, said preliminary reports indicated more buildings and more people may have been injured in Wednesday's aftershock, the Herald said.
"There could be people trapped," Morton said, "but the initial impression is that the additional damage is not hugely significant compared to the initial quake."
Aid was still slow in reaching areas beyond Port-au-Prince because of roads needing to be cleared, The Miami Herald said.
The U.N. Development Program said Wednesday it hired nearly 400 Haitians, paying them in cash to help deliver humanitarian supplies. Officials of the program said they planned to hire another 700 people by the end of the week to remove rubble and repair streets.
Getting around Port-au-Prince remains challenging, Gates said during a media availability in New Delhi, expressing hope that more routes will be cleared within the next 24 to 48 hours so trucks can deliver more aid.
Among the dead from last week's quake are three women instrumental in Haiti's women's and human rights movements. Myriam Merlet, Magalie Marcelin and Anne Marie Coriolan, founders of three of the country's organizations working on behalf of women and girls, were among those confirmed dead, CNN reported.
"Words are missing for me. I lost a large chunk of my personal, political and social life," Carolle Charles said in an e-mail. Charles called the women "my friends, my colleagues and my associates. I cannot envision going to Haiti without seeing them."
The Pentagon reported the hospital ship USNS Comfort received patients Tuesday as it was heading toward Haiti. The patients -- a 6-year-old boy and 20-year-old man, both in serious condition -- were treated on board the aircraft carrier USS Carl Vinson before being sent to the floating hospital.