Tokyo will be paying an estimated $26 billion or more to implement the overall U.S. military realignment in Japan over six to seven years, compared with Washington's share of $4 billion, a senior Pentagon official said Tuesday.

Richard Lawless, deputy defense undersecretary for Asia and Pacific affairs, unveiled the estimates at a news conference when repeatedly asked why the United States struck a compromise Sunday with Japan on sharing the cost for relocating 8,000 marines to Guam from Okinawa.

Japan agreed to pay $6.09 billion, or 59 percent, of the $10.27 billion total relocation cost through grants, investment and loans. The U.S. had asked Japan to pay $7.5 billion, or 75 percent, of the earlier estimated cost of $10 billion.

"The only cost to the United States is $4 billion on Guam," Lawless said, arguing the deal was a "fairly struck bargain" in the broader context of Japan shouldering all the costs for changes within Japan, including the relocation of the marines' Futenma Air Station in Okinawa, on top of its Guam share.