(CNN) -- Twitter was buzzing Thursday morning with news that several airlines are flying doctors and nurses to Haiti free of charge to help with relief efforts there in the wake of Tuesday's devastating earthquake. The only problem: The rumors are false, an American Airlines spokesman says. "Last night's hoax on Twitter about American and JetBlue flying doctors and nurses to Haiti for free was just that -- a hoax. We don't know who is responsible, but it's a very low thing to do," airline spokesman Tim Smith said in e-mails sent Thursday. Twitter users also circulated a rumor that UPS would ship for free any package under 50 lbs. to Haiti. In a blog post Wednesday on UPS's Web site, a spokeswoman debunked the rumor and said that destruction of Haiti's roads and communications networks "means our own shipping services to Haiti are on hold."
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Rumors spread on Twitter on Thursday about airlines flying doctors to Haiti free of charge
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American Airlines spokesman calls the rumors a hoax
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Rumors also spread that JetBlue is offering free flights and UPS is shipping packages for free
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Both airlines say they are working with relief agencies to fly in supplies and personnel
And I think that's where these rumors are coming from," @placeholder spokeswoman Alison Croyle said.