The foreign minister of the Marshall Islands on Thursday called for more U.S. money to deal with the legacy of massive U.S. nuclear testing to enable the renewal of a strategic agreement governing bilateral relations.

Marshall Islanders are still plagued by health and environmental effects of 67 U.S. nuclear bomb tests from 1946 to 1958, which included "Castle Bravo" at Bikini Atoll in 1954, the largest U.S. bomb ever detonated.

The 67 U.S. atmospheric nuclear weapons tests at Bikini Atoll and 44 at Enewetak Atoll spewed radiation over the Marshall Islands and produced a total explosive power of 108.5 megatons, equaling the energy yield of 7,000 Hiroshima bombs.

As a result, cancer rates have doubled in some places, displaced people have waited decades to return to their homes, and radiation still plagues the land and waters of this Pacific island nation. But to this day, the only individuals considered by the U.S. as exposed to radiation effects were those physically present at Rogelap, Ailinginae or Utrok atolls at the time of the "Castle Bravo" nuclear test.

Foreign Minister Jack Ading told a U.S. congressional hearing a memorandum of understanding on terms to extend his country's Compact of Free Association (COFA) with Washington was signed in January without proper domestic authorization and under pressure of a deadline for inclusion in President Joe Biden's budget.

"There are other issues that needed to be included, and especially, additional funding for the nuclear-affected populations," he told the Senate Committee on Energy and Natural Resources, appealing to Congress to direct the Biden Administration to continue negotiating.

The Marshall Islands is one of three Pacific island nations covered by COFAs, under which the U.S. has responsibility for their defense and provides economic assistance, while gaining exclusive access to huge strategic swathes of the Pacific.

Under MOUs agreed this year, the U.S. will commit a total of $7.1 billion over 20 years to the three nations.

In May, the U.S. said it had finalized COFA terms with Micronesia and Palau and hoped do so with the Marshall Islands in coming weeks. The economic terms of its existing COFA expire at the end of the fiscal year on September 30.

More than 100 activist groups have urged Washington to formally apologize to the Marshall Islands and provide fair compensation.

Chief U.S. negotiator Joseph Yun told the hearing he was "puzzled" by the Marshall Islands' position, given the MOU offered it $2.3 billion over 20 years and that the nuclear liability issue had been "settled" in the 1980s.

Yun said he had told Marshallese islanders that "there is no more money," and the $7.1 billion total is "a very generous offer." He added that he was optimistic that Congress will enact the legislation.

Yun told the committee he believed domestic politics was at play in the Marshall Islands, with an election in November and rumors President David Kabua could face a no-confidence motion.

Denying this, Ading said he was "saddened and disappointed" by the reference to internal affairs.

(With input from Reuters)