South Korea has postponed the introduction of aerial refueling tankers by about a year until 2018 due to a delayed process of selecting a successful bidder, government officials and industry sources here said Friday.

The 1.4 trillion won ($1.26 billion) project to purchase four refueling tankers has drawn interest from three aerospace giants: Europe's Airbus Defense and Space, Boeing of the United States and Israel Aerospace Industries (IAI) of Israel.

The Defense Acquisition Program Administration (DAPA), South Korea's state arms procurer, had planned to choose the winning bidder by the end of last year, but the process has been delayed due mainly to gaps in offsets of defense trade terms, according to industry sources.

Offsets in defense trade encompass a range of industrial compensation arrangements required by foreign governments as a condition of the purchase of defense articles and services from a non-domestic source.

"We will resume negotiations with the candidates next week," said a DAPA official, requesting anonymity. "After wrapping up the talks and bidding process by the end of next month, we will make a contractor selection in June."

The delay in the selection process has subsequently caused the military's schedule of putting the tankers into service to be postponed from 2017 to 2018, a defense ministry official said.

"But we are to deploy all four tankers by 2019 as planned -- two in 2018 and two in 2019," the official noted.

The use of tankers allows the fighter jets to stay airborne for an extra hour and carry more weapons. The greater payload is made possible because the jets can take off with less fuel, thereby lightening their weight. (Yonhap)