Just a few weeks ago, it seemed that the U.N. General Assembly in New York would be a possible venue for the leaders of the United States and Iran to sit down for historic talks amid their standoff over a 2015 nuclear deal.

The chance, however, slipped away in the wake of the Sept. 14 attacks on Saudi Arabian oil facilities, with the United States quickly putting the blame on Iran and even signaling the possibility of military actions in retaliation.

As world leaders gathered for the U.N. meetings, Japanese Prime Minister Shinzo Abe sought to use the arena to call on both U.S. President Donald Trump and Iranian President Hassan Rouhani to work toward de-escalating the tensions in the Middle East, a critical region for the resource-poor Asian country.

"Because the situation is tough, there is something only Japan can do here, given its alliance relationship with the United States and the long-standing amicable ties with Iran," Abe said at a press conference on Wednesday in wrapping up his visit to New York.

As part of the delicate balancing act, Abe refrained from naming any specific country to be blamed for the attacks, even after Britain, France and Germany joined the United States in accusing Iran on Monday.

Abe also remained elusive on whether Japan will join a U.S.-led international maritime security coalition to safeguard commercial shipping in key waterways off Iran and Yemen.

But some foreign policy experts warn that not making any actual contributions to deter threats to shipping lanes may fall short of Japan's own commitment to become a "proactive contributor to peace," a mantra Abe has used for years after taking office in 2012.

"You cannot talk about proactive contributions to peace...and freedom of navigation for six, seven years, and then when that very thing is in danger, to sit on the sidelines and not make any decision about it," said Jeffrey Hornung, a political scientist at the Rand Corporation, a U.S. research organization.

The U.S. idea to form a coalition by bringing together military assets from other countries has taken shape following a series of attacks in May and June on oil tankers in the Gulf region, including one operated by a Japanese company.

Five countries have joined the coalition, with Saudi Arabia and the United Arab Emirates becoming part of the framework soon after the Sept. 14 attacks. The three other countries are Australia, Bahrain and Britain.

But due to economic interests in Iran, many countries have expressed reservations or signaled distance from the Trump administration, which pulled out of the multinational deal to curb Iran's nuclear program.

Japan has not clarified its stance on the issue apparently from fear of hindering its relationship with Iran as well as caution over the prospect of sending its Self-Defense Forces overseas, as entanglement in a foreign conflict could violate the country's post-World War II pacifist Constitution.

Hornung said Abe is simply being "saved" from criticism at the moment because the international community has not been united on the issue.

But he said Japan could face increased pressure from the United States to make contributions toward beefing up maritime security in the Middle East as more time passes and as rising tensions affect fuel supplies.

"Sitting on the sidelines is the worst thing Mr. Abe can do. He needs to make a definitive statement on 'we are going to join,' or 'we're not going to join,' or 'we're going to do our own thing,' and explain it preemptively," Hornung said, adding that Japan would otherwise look "reactive" rather than "proactive."

Japan has bitter memories of its so-called checkbook diplomacy -- a criticism it faced from the United States and other countries over its support for U.S.-led forces during the 1991 Gulf War that took the form of money and not troops.

Trump complained on Twitter in June that the United States is protecting shipping lanes in the Middle East for other major oil importers, such as China and Japan, for "zero compensation." He said, "All of those countries should be protecting their own ships."

Tetsuo Kotani, an associate professor at Japan's Meikai University, also said it is no longer possible to ride out the situation without Japan offering actual contributions for maritime security in the Middle East, a region on which the country relies for more than 80 percent of its oil imports.

But he said Japan can choose less controversial options than joining the U.S.-led coalition. For example, the SDF can carry out surveillance activities off Yemen by diverting its forces that are already engaging in anti-piracy operations off Somalia.

Tehran may not strongly react to such missions as long as Japan opts to act outside the U.S.-led initiative, even though the area of operations would likely overlap.

Kotani also noted that Trump may not be too focused on the idea of a coalition, given that he has not mentioned the word in public so far, which suggests that the idea carries more weight among U.S. diplomats and the military than with the president himself.

"This makes me believe that the president is currently expecting Japan to act as a go-between (for dialogue with Iran). And if so, he would not ask Japan to join the coalition for now, which will certainly work negatively (in coaxing Iran)," the expert on the Japan-U.S. alliance said.

If that is the case, the important thing for Japan may be to show other countries that it is taking at least some action to better safeguard the waterways in the Middle East, Kotani said.