(CNN) -- A top United Nations official acknowledged Friday that the earthquake relief operation in Haiti was not progressing fast enough.
"You can't snap your fingers and make it happen just by magic," U.N. Emergency Relief Coordinator John Holmes said. But he promised, "We will do it, slowly and surely."
In an interview with CNN's Christiane Amanpour, Holmes said, "We have blockages at different points or bottlenecks of different points. The airport, coming in -- not as many planes as we'd like to get in there because of the landing blockages. It's happening, but it's happening not as fast as we would like."
Referring to the slow pace of aid deliveries, Holmes added, "We've got to unload it, get it into warehouses, then get it into trucks, then get it to distribution points, and then start to distribute it."
"There's a huge effort going in from huge numbers of countries and aid organizations, but it's not so visible on the ground because you can't quite get it there."
Holmes said it was key to dig out survivors from ruined buildings as soon as possible. "There are something like 27 search-and-rescue teams now either on the ground or on their way, and that's beginning to make a difference," he said.
"Of course, with every day that passes, we know that the chances of finding somebody alive diminish, but that effort must continue, and we must continue to try and look after the injured."
New York City Police Commissioner Ray Kelly, who was in Haiti just before the earthquake and served there in the mid-1990s, also emphasized the importance of saving the lives of people who are trapped and injured.
"I think there's still an opportunity even though it's almost 72 hours. I think that's got to be job number one," Kelly told Amanpour.
As far as aid distribution is concerned, Kelly said it was essential to move supplies from the airport into Port-au-Prince as fast as possible.
"It's about five miles for the most part, but it's a tough five miles. The roads are not good. Perhaps the helicopters from the USS Carl Vinson are going to be used to do precisely that."
The USS Carl Vinson, an U.S. Navy aircraft carrier, has recently arrived off the coast of Haiti with a fleet of 19 helicopters and several tons of aid.
Holmes expressed concern about the losses faced by the Haitian National Police during the earthquake. He said 300 officers died when the main police commissariat collapsed.
"It's not surprising they haven't been able to recover from the blow. But the prime minister, the president, are functioning now, and the ministry of interior."
He said so far it has been reasonably calm in Haiti. But the U.N. has thousands of police and soldiers in the country, and they will be able to maintain law and order with the help of American troops if necessary, Holmes said.
"It's really a peaceful country. I think it's gotten a bad reputation for certain outbreaks that did happen," Kelly said. "The people are in desperate straits. But I think everyone will be surprised at just how peaceful and orderly it will be."