But he added that he was not sure Okinawans will be satisfied with measures to cut back military landholdings and otherwise reduce friction over troops on the southern island.
Mr Mondale said recent tensions involving Taiwan and North Korea reinforced the importance of the US-Japan security relationship, to be reaffirmed during President Bill Clinton's visit to Japan next week.
The rape of a 12-year-old girl by three American servicemen last August ignited protests against US bases on Okinawa, which hosts more than half the 47,000 US troops in Japan. Amid the outcry, a joint US-Japan committee was set up in November to look into ways to consolidate bases on Okinawa.
Both US embassy and Japanese foreign ministry officials refused to comment on a report in the Yomiuri newspaper saying the pact would call for America to return 12,350 acres to landowners on Okinawa. The report said the plan does not call for the return of Futemma Air Base, which has topped the Okinawans' priority list because it is in the middle of a city.
US officials also have agreed to a ban on uniformed marches off base and stricter restrictions on night flights. Mr Mondale was uncertain whether he expected the moves to satisfy the Okinawans, but he said the US had "really tried" to address their concerns.
"There's been more effort in the last six months than in the last 20 years," he said, adding that a reassessment of the US military role was long overdue.
Both governments have said US troop levels in Japan would remain constant, though some troops may be moved to other parts of the country. Okinawa's government has drawn up plans for the complete withdrawal of troops from the island by 2015.
Meanwhile, more than 3,000 people living near an air base outside Tokyo yesterday filed a law suit demanding 3.3bn yen (pounds 20m) compensation from both governments for noise .Reuse content