At least seven people have been killed and 100 are missing after an overnight landslide in the southern Mexican state of Oaxaca, officials have said. Heavy rain saturated a 200m (656ft) wide strip of mountainside above the town of Santa Maria Tlahuitoltepec. Oaxaca's governor earlier said between 100 and 300 homes had been buried, with as many as 600 people sleeping inside. Rescue teams have struggled to reach the area because the roads are cut off. "There has been lots of rain, rivers have overflowed and we're having a hard time reaching the area because there are landslides on the roads," Oaxaca state governor Ulises Ruiz told the Televisa network. He said local telephone lines had been cut off. Mr Ruiz added that municipal authorities had told him by satellite phone that the landslide had buried 100 to 300 houses, and speculated that 500 to 600 people could have been asleep inside at the time. "They're talking about up to 1,000 people," he said.