The group - fighting for the mainly ethnic-Somali Ogaden's independence - was responding to the country's mines and energy minister, Alemayehu Tegenu, who last week said the area was secure.

"(Alemayehu's) claim that his regime's military is in control of Ogaden is wishful thinking and is designed to give a false sense of security to oil firms who seek to exploit the oil resources of Ogaden," an ONLF statement said in a Reuters report.

"The renewal of security assurances for Ogaden by the regime to oil firms is therefore a dangerous step as the policy of the ONLF in this regard remains unchanged."

Alemayehu said the government was in negotiations to give three more foreign mineral firms licenses to explore for oil and gas in the Horn of Africa country. He did not say whether the sites were in the Ogaden.

Ethiopia said the Ogaden basin may contain gas reserves of 4 trillion cubic feet and points to oil-producing neighbours such as Sudan and Yemen as evidence there could be major oil deposits.

Apart from a small discovery of natural gas, no significant oil or gas finds have been made. Twelve foreign firms, including Vancouver-based Africa Oil Corporation and Malaysia's Petronas, are exploring Ethiopia's deserts.