PLEASANT GROVE, Alabama (Reuters) – The government ramped up efforts on Saturday to help thousands of homeless victims of the country's second deadliest recorded tornado outbreak, which killed at least 350 people.

President Barack Obama, who surveyed the tornado destruction in the worst-hit state of Alabama on Friday and called it "heartbreaking," was sending top officials to the disaster zone this weekend to escalate federal assistance.

With some estimates putting the number of homes and buildings destroyed at close to 10,000, state and federal authorities in the U.S. South were still coming to terms with the scale of this week's devastation from the country's worst natural catastrophe since Hurricane Katrina in 2005.

Thousands of stunned survivors, many of whom had seen relatives and friends killed by twisters that obliterated whole communities, were camped out in the shattered shells of their homes or moved into shelters or with friends.

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