The foreign ministers of South Korea and Japan said Monday they had reached a deal meant to resolve a decades-long impasse over Korean women forced into Japanese military-run brothels during World War II, a potentially dramatic breakthrough between the Northeast Asian neighbors and rivals.The deal, which included an apology from Japanese Prime Minister Shinzo Abe and a 1 billion yen ($8.3 million) aid fund from Tokyo for the elderly former sex slaves, could reverse decades of animosity and mistrust between the thriving democracies, trade partners and staunch U.S. allies.The issue of former Korean sex slaves, euphemistically known as "comfort women," has been the biggest source of friction in ties between Seoul and Tokyo, with animosity rising precipitously since the hawkish Abe's 2012 inauguration.Japan appeared emboldened to make the overture after the first formal leaders' meeting between the neighbors in 3,5 years, in November, and after South Korean courts recently acquitted a Japanese reporter charged with defaming South Korea's president and refused to review a complaint by a South Korean seeking individual compensation for Japan's forceful mobilization of workers during colonial days.Many South Koreans feel lingering bitterness from the legacy of Japan's brutal colonial occupation of the Korean Peninsula from 1910-1945. But South Korean officials have also faced calls to improve ties with Japan, the world's No. 3 economy and a regional powerhouse, not least from U.S. officials eager for a strong united front against a rising China and North Korea's pursuit of nuclear-armed missiles that could target the American mainland.Japanese Foreign Minister Fumio Kishida and his South Korean counterpart, Yun Byung-se, made the announcement after their closed door meeting Monday.Yun said the agreement is final and irreversible as long as Japan faithfully implements it promises."Abe, as the prime minister of Japan, offers from his heart an apology and reflection for everyone who suffered lots of pain and received scars that are difficult to heal physically and mentally," Kishida told the same news conference.There has long been resistance in South Korea to past Japanese apologies because many here wanted Japan to acknowledge that it has a legal responsibility for the women. Japan, for its part, had long argued that the issue was settled by a 1965 treaty that restored diplomatic ties and was accompanied by more than $800 million in economic aid and loans from Tokyo to Seoul.Historians say tens of thousands of women from around Asia, many of them Korean, were sent to front-line military brothels to provide sex to Japanese soldiers. In South Korea, there are 46 such surviving former sex slaves, mostly in their late 80s or early 90s.Better relations between South Korea and Japan are a priority for Washington. The two countries together host about 80,000 U.S. troops and are members of now-stalled regional talks aimed at ending North Korea's nuclear ambitions in return for aid.