PUERTO ESCONDIDO, Mexico, Sept 23 (Reuters) - Mexico's

top disaster agency issued a red alert for parts of the

country's southern Pacific coast on Monday after Hurricane John

rapidly strengthened to a Category 2 storm and threatened to get

stronger before making landfall in the coming hours.

The national Civil Protection agency issued its most serious

warning for coastal regions of Mexico's southern Guerrero and

Oaxaca states, warning residents to seek shelter until

authorities give the all-clear.

The agency said the storm's current path put it on track to

make landfall between Copala, Guerrero, and Santiago Pinotepa

Nacional, Oaxaca, between 9 p.m. (0300 GMT) and 1 a.m. local

time.

The U.S. National Hurricane Center (NHC) warned of

"imminent" flooding, storm surges, and hurricane-force winds as

the storm loomed just about 30 miles (48 km) from Guerrero's

Punta Maldonado early on Monday evening, blowing maximum

sustained winds of 105 miles per hour (170 kph).

The storm was likely to intensify before making landfall

late on Monday or early Tuesday, the Miami-based hurricane

center said in a statement.

"John could become a major hurricane before making landfall

along the coast of southern Mexico," the NHC said.

In the typically laid-back surfer getaway of Puerto

Escondido, Oaxaca, residents on Monday hurried to tow in boats

and put away beach chairs.

"We're very concerned," said restaurant-owner Paula Sanchez,

who said hurricanes in the area had become stronger in recent

years.

"Let's hope that God will divert (this storm)," Sanchez

added.

Education officials announced school closures in parts of

Oaxaca and Guerrero as the storm approached, and Mexico's state

power firm CFE said it was moving worker convoys to Oaxaca ahead

of John's arrival.

A hurricane warning is in place for areas from the famous

beach resort of Acapulco, which is still recovering from last

year's Hurricane Otis, as far east as the Oaxacan tourist hub of

Huatulco.

A tropical storm warning stretched east of Huatulco to the

major port of Salina Cruz, home of Mexican state-run oil company

Pemex's largest domestic refinery.

NHC warned that heavy rainfall from John may cause

"significant and possibly catastrophic, life-threatening flash

flooding and mudslides," that will affect the Mexican states of

Chiapas, Oaxaca and southeast Guerrero through Thursday.

(Reporting by Brendan O'Boyle, Diego Ore, Kylie Madry and Aida

Pelaez-Fernandez in Mexico City and Fredy Garcia in Puerto

Escondido; Writing by Brendan O'Boyle; Editing by Alistair

Bell, Stephen Coates and Lincoln Feast.)