LONDON (AlertNet) - Haitians injured in a massive earthquake are suffering severe trauma but stretched medical teams can only offer basic first aid care, medical charity Medecins Sans Frontieres said on Wednesday.

MSF, which employs 800 medical staff in Haiti, said three free medical centres it runs had been badly damaged in the 7.0 magnitude quake that rocked Haiti on Tuesday and workers were operating out of temporary shelters.

"We're seeing a massive influx of patients but the best we can offer at the moment is first aid care," said Paul McPhun, a member of MSF's emergency management team, on a conference call with journalists.

"We're seeing severe trauma, crushed lungs ... the level of care we can provide without the infrastructure is very limited. All the main hospitals we'd normally make referrals to in the immediate vicinity of Port-au-Prince are collapsed or abandoned," added McPhun, who was speaking from Toronto.

MSF is trying to identify a structure to turn into a hospital.

With mobile phone networks largely down, MSF, like other charities, is struggling to locate all its workers. MSF has not accounted for all its staff and local staff members are also concerned about their families.

"The situation is very chaotic. Information is very difficult to gather," McPhun said.

"Last night we had teams working all night, we were mobbed by crowds of people, more because they had desperate needs than because of any animosity. We're all familiar with Haiti and how difficult it is to keep things stable. There are real security concerns," he added.

Haiti is one of the world's poorest countries that is still rebuilding after a series of hurricanes in late 2008 killed hundreds of people and destroyed fragile infrastructure.

Some 70 international MSF volunteers and staff have already been identified and are ready to fly in to Haiti but access is a problem. Aid workers from many charities are descending on the Dominican Republic but it is unclear how they will get to Port-au-Prince. Passenger flights have been suspended.

"We don't have a shortage of people willing to go, it's how to get them there," said McPhun.

Medical relief charity Merlin is sending its own team of four people that expects to be on the ground by Friday.

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