Japanese Prime Minister Shinzo Abe and U.S. President Donald Trump agreed Friday to bolster the "unwavering" bilateral alliance after Trump earlier revived his criticism of what he sees as a one-sided security treaty.

Meeting for the third month in a row and just ahead of the two-day Group of 20 summit in Osaka, the two leaders also agreed to work closely in dealing with regional issues such as North Korea and accelerate ongoing bilateral trade talks to achieve results at "an early date," according to a Japanese government official.

"These frequent visits between the leaders in such a short period of time are evidence of the robust Japan-U.S. alliance," Abe said at the outset of their meeting.

While the two leaders have been known for enjoying personal rapport, Japanese and U.S. government officials have recently been scrambling to deny a report by Bloomberg news agency earlier this week that Trump mused to confidants about withdrawing from the security treaty, a key part of the postwar Japan-U.S. relationship.

Trump even appeared to double down on his arguments when he openly showed his discontent with the treaty on Wednesday on Fox Business Network.

"If Japan is attacked, we will fight World War III. We will go in and we will protect them and we will fight with our lives and with our treasure...but if we're attacked, Japan doesn't have to help us at all. They can watch it on a Sony television, the attack," he said.

The remarks are similar to those Trump voiced during the 2016 presidential campaign, but political observers have speculated that the reason he may have revived the argument was to gain leverage over the trade negotiations by reminding Japan of its heavy reliance on defense.

In the latest effort to play down the concerns, Deputy Chief Cabinet Secretary Yasutoshi Nishimura, who briefed reporters on the Abe-Trump meeting, said, "There were no such discussions at all on reviewing the Japan-U.S. security treaty."

"The two leaders agreed to further strengthen the unwavering Japan-U.S. alliance," he added. But at the same time Nishimura admitted that Abe did not ask Trump directly about his intentions behind the remarks criticizing the long-standing treaty.

The White House separately said they "confirmed their intent to deepen and expand U.S.-Japan alliance cooperation around the globe."

The security pact requires the United States to come to the defense of Japan in the event of an attack. Around 50,000 U.S. troops are stationed in Japan, which has renounced war under its postwar Constitution, enabling the United States to respond rapidly to contingencies in the Asia-Pacific region, including North Korea.

During the 35-minute talks with Trump, Abe also called for diplomatic efforts among relevant parties to ease rising tensions in the Middle East stemming from the confrontation between the United States and Iran over a global nuclear deal reached in 2015.

With Japan long enjoying amicable ties with Iran, Abe made a two-day visit there earlier in the month in an apparent bid to serve as a bridge between Washington and Tehran.

But tensions spiked after two oil tankers, one operated by a Japanese company, were attacked near the Strait of Hormuz, a critical route for oil shipments from the region. Trump also came close to launching a military strike against Iran, which downed a U.S. drone last week.

On North Korea, Abe and Trump agreed to continue to fully implement the U.N. Security Council resolutions imposed on the country for its nuclear and missile programs, according to Nishimura.

Trump reiterated his "full support" to Abe's resolve to meet North Korean leader Kim Jong Un in the hope of settling the issue of Pyongyang's past abduction of Japanese nationals, he said.

While the Japanese side appeared to be largely focusing on highlighting the stable relationship of the two allies, Trump suggested at the beginning of the meeting that his attention is on trade, and hailed the growing U.S. investments by Japan automakers.

Trump and Abe agreed that their bilateral trade deal should benefit both sides, although the timeline of when to reach a conclusion was not discussed, according to Nishimura.

The negotiations at the ministerial level started in mid-April as part of Trump's push to reduce his country's large trade deficit and increase jobs. Trump again touched on the deficit issue during the latest meeting, according to a Japanese government source.

The two countries previously agreed to reach a deal after Japan's House of Councillors election in July.

As the chairman of the G-20 gathering, Abe sought cooperation from Trump so that members can come up with a powerful message toward achieving sustainable growth of the world economy and other global challenges, saying that those cannot be addressed without the two countries working together.