Japan will introduce four airborne refueling planes to help extend the flight range of Self-Defense Forces aircraft in its midterm defense buildup plan for the five years from fiscal 2001, coalition sources said Thursday.

In drafting the budget for fiscal 2001, which begins April 1, the government will seek appropriations for "research costs" to prepare for the introduction of the aerial tankers, they said.

Within the tripartite coalition, New Komeito had voiced concern over including aerial tankers in the next five-year midterm defense plan.

Their concern, echoed by some key members of the ruling Liberal Democratic Party, stemmed from their belief that, given Japan's "defense-only" defense policy, it does not require aerial tankers and the purchases could cause concern in neighboring countries.

However, New Komeito on Thursday decided to approve the new planes because the plan had already been decided upon last year by the government's Security Council of Japan, chaired by the prime minister, and because they were told the refueling planes would be useful for humanitarian aid operations, New Komeito officials said.

New Komeito Secretary General Tetsuzo Fuyushiba told Thursday's meeting of party executives: "We had been opposed because neighboring countries did not possess any (refueling planes), but China does now possess them. There has been a change in circumstances."

The Defense Agency has been requesting the introduction of aerial tankers to refuel fighters and early-warning aircraft in flight and extend their ranges. This would enable them to help spot aircraft that escape ground-radar detection as well as help reduce fuel costs during military drills.

Following Thursday's decision, the defense buildup plan for fiscal 2001-2005 will state that the four aerial tankers will be introduced within the five-year period, the sources said.

The plan will justify the new aerial tankers on the grounds that they will help prevent accidents, reduce aircraft noise pollution, enable the defense forces to respond more swiftly during cooperative international missions and be used as additional transport vehicles as well, the sources said.

Chief Cabinet Secretary Yasuo Fukuda is expected to announce that the Security Council of Japan will select which aircraft are to be purchased after careful deliberation.