SOFIA (Reuters) - Bulgaria’s president has criticized a planned visit by defense officials to Washington just as the country seeks bids to supply warplanes from the United States and several other countries.

FILE PHOTO - Bulgaria's President Rumen Radev arrives for the second day of a NATO summit in Brussels, Belgium, July 12, 2018. Tatyana Zenkovich/Pool via REUTERS

The defense ministry had on Tuesday said a delegation led by Deputy Minister Atanas Zapryanov will visit the United States next week after an invitation from the U.S. Embassy in Sofia.

But President Rumen Radev, a former air force commander, said on Thursday the visit could put some of the possible bidders in a less favorable position.

“In countries where there is equal treatment, no meetings, visits or talks are held from the moment of sending invitations for offers for aircraft supply until their submission,” Radev said.

Last month the Black Sea state, which joined NATO in 2004, sent a request for proposals (RFP) to Portugal, Israel, Italy, Germany, France and Sweden for 16 new or used fighter jets to replace its aging Soviet-designed MiG-29s.

The question of which warplanes to buy has vexed successive governments in Bulgaria for more than a decade. But NATO is encouraging its eastern members to develop, buy and operate new equipment.

“The only acceptable meeting is a conference at which all participants could receive information,” Radev, elected in November 2016 with backing from the opposition Socialists, said.

Radev said the visit to the United States was a decision of the defense ministry that was not coordinated with him. The president of Bulgaria is also the chief commander of the military of the country.

The defense ministry was not immediately available for comment.

In June Bulgaria’s parliament approved a plan to buy the jets in two equal stages. Some 1.8 billion levs ($1 billion) will cover the first eight aircraft, as well as ground handling, team training and three years of initial logistics support.

Potential options include Boeing’s F/A-18 Super Hornet, Saab’s Gripen, Dassault’s Rafale and Lockheed Martin’s F-16 or the Eurofighter. Sofia is asking manufacturers to make bids by Oct. 1.

($1 = 1.7096 leva)