Ethiopia insisted on Friday that its airspace was safe after the United States warned of a possible risk to civilian aircraft because of the spiralling conflict.
The Federal Aviation Administration this week advised US carriers to exercise caution while flying into or near Addis Ababa, as the year-long war moves closer to the Ethiopian capital.
Airlines "should plan to exercise caution during flight operations due to the potential inadvertant risk to civil aviation operating in or near areas of fighting," it said in a statement.
"Civil aircraft may be directly or indirectly exposed to ground weapons fire and/or surface-to-air fire."
But the Ethiopian Civil Aviation Authority dismissed the US warning as "baseless and quite contradictory to the reality".
"Ethiopian Civil Aviation Authority would like to state that any flight in Ethiopian airspace including Addis Ababa international airport is safe and secured."
The government declared a nationwide state of emergency earlier this month and ordered Addis Ababa residents to prepare to defend their neighbourhoods amid fears that rebels from the northern region of Tigray were heading for the capital.
The US embassy has evacuated non-essential staff and is urging US citizens to leave the country while commercial flights are available.
Washington has been among the most vocal critics of the war in Africa's second most populous nation, which has killed thousands of people and driven hundreds of thousands to the brink of starvation.
Top US envoy Jeffrey Feltman was in Ethiopia this week, along with his African Union counterpart, former Nigerian President Olusegun Obasanjo, as part of intensifying efforts to try to end the war.
Getachew Reda, spokesman for the rebel Tigray People's Liberation Front (TPLF), said Friday that Obasanjo had travelled to Tigray for "extensive discussions" with the group's leadership.
"They... agreed to continue to engage in the pursuit of peace and stability in the country," Getachew said on Twitter.
US Secretary of State Antony Blinken on Wednesday renewed Washington's call for a ceasefire during a visit to Kenya, after warning last week that Ethiopia risked "implosion" unless the government and the TPLF negotiate a deal.
Obasanjo had warned Sunday that peace talks "cannot deliver" without an immediate halt to the fighting.