Japanese Prime Minister Shinzo Abe was put in a complicated situation at the Group of Seven summit in Canada as he tried to bridge the gap between the United States and other members over controversial new U.S. metals tariffs.

Abe stressed the members' unity in support of fair trade while refraining from directly repeating Japan's concern about the U.S. levies during the two-day summit in Quebec's Charlevoix. But U.S. President Donald Trump's abrupt rejection of the joint communique and angry tweets left the annual meeting in disarray.

Canadian Prime Minister Justin Trudeau, who chaired the summit, expressed his disappointment over Washington's recent decision to impose new tariffs on steel and aluminum in a post-meeting press conference, and Trump responded by calling him "very dishonest and weak," backing off from the communique he signed hours earlier.

Takumi Shibaike, a doctoral candidate in political science at the University of Toronto, said Abe has to perform a balancing act as the leader of a country that is facing both U.S. tariffs and the North Korean threat.

Abe is desperate to garner support from Trump in dealing with North Korea, in particular to move forward the issue of Japanese nationals abducted by Pyongyang in the 1970s and 1980s, one of his government's top priorities.

Trump is set to meet with the North's leader Kim Jong Un on Tuesday in Singapore in the first-ever U.S.-North Korean summit.

While G-7 members have been sharing concerns over North Korea, disputes with the United States over trade have been escalating.

Even before arriving in Charlevoix, the American leader drew fire from his G-7 peers for new tariffs on imported steel and aluminum products, including those from Canada and the European Union. Japan has already been subject to the levies as part of Trump's "America First" policies.

Before leaving Washington for Quebec, Trump abruptly recommended that Russia be brought back into the G-7, further fueling the disharmony among members.

Under his administration, the world's largest economy has undermined the multilateral orders it created and given up its leading role in the G-7 as promoter of free and fair global trade based on World Trade Organization rules, economics say.

Japan's Deputy Chief Cabinet Secretary Yasutoshi Nishimura, who briefed reporters after the first day of the summit, admitted that there "were lots of critical comments" about the U.S. metal tariffs.

Trump is seeking additional tariffs of as much as 25 percent on automobile imports, up from 2.5 percent, in a move that, if realized, could deal a huge blow to Japan and Germany, major car exporters.

Amid growing speculation that the G-7 leaders would not be able to agree on a post-summit communique, Trudeau managed to issue a statement signed by all the participating leaders.

Hitoshi Suzuki, an associate professor of European international relations at the University of Niigata Prefecture, said the leaders' statement matters because issuing one is the "raison d'etre" of the G-7.

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On North Korea, Abe called on other G-7 members to support Trump ahead of the summit with Kim.

"Donald will face one of the most important meetings in the century in four days. The G-7 must come together to support him," Abe was quoted by Nishimura as saying in Friday's session on security.

Abe has repeatedly urged Trump to take up the abduction issue in his upcoming summit with Kim, arranging talks in Washington en route to the annual G-7 gathering to press the point home to the U.S. leader.

Abe is considered to have a big voice at the G-7 summit given that he is one of the second longest-serving leaders after German Chancellor Angela Merkel, Suzuki said.

With the summit ending in a war of words, Abe's attempt to defuse the conflict over U.S. trade policy during the meeting apparently had little effect on Trump after all.

Shibaike said there was little the Japanese prime minister could have done except "take a back seat on the trade issue while seeking reassurance that the United States and Japan are on the same page regarding North Korea."