UPDATE 1-Tropical depression in Gulf of Mexico strengthens, closes ports
* Depression expected to strengthen into tropical storm
* Two top oil export terminals closed
* But closure of export hubs not uncommon during hurricane season
(Updates storm progress, adds details on nearby oil facilities)
MEXICO CITY, Sept 12 (Reuters) - A tropical depression in the southern Gulf of Mexico is strengthening, prompting the closure of two top oil export terminals, and could unleash life-threatening flooding, the U.S. National Hurricane Center (NHC) said on Thursday.
The depression, called Ten, was expected to strengthen over the next 24 hours into a tropical storm, the center said.
The country's two biggest oil export terminals, Dos Bocas and Cayo Arcas, were closed, the government said, although the port of Coatzacoalcos remained open.
The closure of oil export hubs during the hurricane season is not uncommon and unless the closures persist for days, they rarely affect overall export deliveries.
An official with state oil monopoly Pemex said the company was closely monitoring the depression, but that so far there had been no installation closures or impact on operations.
Pemex's most productive oil fields are located in the vicinity of the depression, in the shallow waters of the Bay of Campeche. The company's Lazaro Cardenas refinery in Veracruz state appears to be in its path.
The center of the slow-moving depression is located 165 miles (270 km) north-northeast of the coastal city of Veracruz, moving at 5 miles per hour (mph) toward land with maximum sustained winds of 35 mph.
The depression is expected to become a tropical storm on Friday, and between 10 to 15 inches of rainfall is projected once it makes landfall, the NHC said.
A tropical storm warning is in effect from the Gulf coast port of Coatzacoalcos north to Barra de Nautla.
(Reporting by NR Sethuraman in Bangalore and David Alire Garcia in Mexico City; Editing by Simon Gardner and Joseph Radford)