The U.S. is stepping up relief efforts for earthquake-torn Haiti. Thousands more U.S. troops have been sent in as earthquake aid and rescue teams try to reach areas outside Port-au-Prince which have received little or no help so far.

Reinforcements arrive in Haiti.

Thousands more US troops have recently reached the earthquake-hit country

This marine corps arrived via warship with bulldozers, diggers and
trucks.

[Lt. Colonel John Golden, U.S. Marine Corps]:
"Geography is our biggest challenge right now. Hasn't really rained for a while and the ground is still pretty soupy. There are just places on this coastline that our vehicles can't get to. That's why we are here. We are going to push out a little bit further."

12,000 US military personnel are now in Haiti or on ships off the coast.

The navy hospital ship Comfort has also just arrived.

It's carrying 600 medical staff and has 250 beds.

There are also 12 operating theatres, four X-ray units and a CAT scanner on board, along with 5,000 units of blood

[Jean Messypor]:
"I am so happy because they are coming to help people in need."

But not everyone is happy.

Some areas have seen little in the way of international aid since the quake hit last Tuesday.

At Morne I'hopital - a residential area on the outskirts of Port au Prince - survivors are desperate.

[Renand Charles, Resident, Morne L'Hopital]:
"The only one to think of is God. We've seen so many victims of the quake. I myself am a victim - I have lost seven members of my family - two sisters, an aunt, two cousins who were at the university and two
nieces."

There are signs of Haitian resilience.

But supplies are hard to come by and when they do they cost more than most people can afford.

[Gustave Jean, Local Resident]:
"They are not helping us. They don't bring us water, or anything, and we didn't have any money before this happened."

The new U.S .arrivals clearly have much work to do.