By Barry Malone

ADDIS ABABA, Sept 2 (Reuters) - Rebel claims thatMalaysia's Petronas has stopped oil and gas exploration inEthiopia are lies and three more firms are in negotiations tostart exploration in the country, its mines minister said onThursday.

Ogaden National Liberation Front (ONLF) separatists andlocal media said state-owned Petronas had pulled out of the Hornof Africa nation after a gas field it was exploring was overrunby the militants in May.

"The rebels took no gas field," Mines and Energy Minister,Alemayehu Tegenu, told Reuters in an interview. "That didn'thappen. Petronas have not ceased operations. They have justsuspended work to evaluate their portfolio."

Petronas have yet to comment on the reports.

The ONLF is fighting for independence for the mainlyethnic-Somali Ogaden and has warned international oil and gascompanies to stay away or face attack.

Firms including Petronas and the Vancouver-based Africa OilCorporation are exploring the Ogaden for potential oil and gasreserves. Twelve foreign mineral firms are exploring Ethiopiafor deposits.

Apart from a small discovery of natural gas, which Petronashas signed a $1.9 million deal to extract, Ethiopia has notuncovered significant oil or gas deposits.

The government says the Ogaden basin may contain gasreserves of 4 trillion cubic feet and points to oil-producingneighbours such as Sudan and Yemen as evidence there could bemajor oil deposits under Ethiopia's vast deserts.

Alemayehu said Ethiopia was secure and the government wasnegotiating new exploration licenses with three foreign firms.He did not name them.

'OUR MILITARY IS IN CONTROL'

"We have no complaints from companies exploring here aboutour security," the minister said. "We have secured them. Ourmilitary is in control."

Alemayehu also said peace negotiations with one faction ofthe ONLF were at an advanced stage. ONLF spokesmen have denied adeal is imminent.

The Ethiopian government has reported some skirmishes withthe rebels in the past six months, but regular accusations fromboth sides are hard to verify. Journalists and aid groups cannotmove in the area without government escorts.

Ethiopian forces launched an assault against the ONLF -- whohave been fighting for more than 20 years -- after a 2007 attackon an oil exploration field owned by a subsidiary of China'sSinopec Corp, Asia's biggest refiner.

"Since that attack, we have secured the area," Alemayehusaid.

A British geologist was shot dead in the Ogaden last Julywhile working for IMC Geophysics International, subcontracted toPetronas. The ONLF denied involvement and the government said'bandits' were responsible.

Analysts say the rebels are incapable of ousting thegovernment but can hamper development and weaken security forcesin the Ogaden with hit-and-run attacks. (Editing by George Obulutsa and James Jukwey)