MEXICO CITY (Reuters) - Mexico's air force flew tons of grain to the southern state of Oaxaca on Friday as protests by teachers opposed to education reform spread across the country and road blocks led to dwindling food supplies in some remote regions.

Tension in the state intensified after eight people died last month in clashes between police and the protesting teachers, and unrest has flared throughout Mexico.

Local media reported protests by factions of Mexico's CNTE teachers union on Friday in the states of Guerrero, Oaxaca, Michoacan, Chiapas, Nuevo Leon and in Mexico City.

The union has blockaded 11 highways in Oaxaca, a hotbed of dissent for protesters opposing President Enrique Pena Nieto's education reform that allows the federal government to remove teachers who fail evaluation exams.

The protests have prevented food trucks from reaching remote coastal villages in Oaxaca, where some of Mexico's poorest people live, the country's federal food distribution chief Juan Manuel Valle said.

Valle said 108 tons of corn would be flown in on a Lockheed C-130 Hercules aircraft by the end of the weekend, with additional provisions on standby in case the situation deteriorated.

Araceli Hernández Ramirez, manager of a grocery store in Puente de Coyula, a small town of some 500 inhabitants close to the beach resort of Huatulco, and located about 146 miles (235 km) from the state capital, said she had no rice, corn or flour.

"There are no products," said Hernandez, waiting for a shipment from Diconsa to supply customers. "They go home empty-handed."

Fifty tons of corn were also sent from the neighboring state of Guerrero by truck, in addition to regular shipments of beans, and rice.

On Friday, Mexico's Secretary of the Interior promised action against the blockades in Oaxaca, saying dialogue with teachers' unions could not continue without respect for citizens' rights.

"Blockades and public damage must end," Miguel Osorio Chong said. "Therefore, soon, we will be taking necessary decisions to allow traffic on strategic routes and supplies for communities."

He did not specify what action the government would take.

Osorio said the protests affected thousands of families, forcing businesses in Oaxaca and neighboring Chiapas to close and impeding shipments of medicine.

A spokesperson for the CNTE union could not be immediately reached for comment.

The protests have affected fuel distribution in parts of Oaxaca, but a Pemex official said operations at Salina Cruz, the company's largest refinery, had not been affected.

(Reporting by Natalie Schachar; Editing by Frank Jack Daniel and Richard Chang)