U.S. President Donald Trump said on September 7 that military action was an option in dealing with North Korea's nuclear threat, but he added that he hoped it could be avoided.
"Military action would certainly be an option. Is it inevitable? Nothing is inevitable," Trump said during a news conference in Washington.
"I would prefer not going the route of the military," Trump said. "If we do use it on North Korea, it will be a very sad day for North Korea."
Tensions have risen to their highest level in decades since Pyongyang announced that it had tested a hydrogen bomb that was capable of being placed on an intercontinental ballistic missile (ICBM) that would put the United States in its range. Washington is proposing a range of new UN sanctions against North Korea following the test.
Earlier on September 7, Russia and Japan said they have agreed that North Korea poses a threat to peace and stability in the region.
However, there was no sign that Moscow has dropped its opposition to the imposition of further UN sanctions on Pyongyang.
Russian President Vladimir Putin and Prime Minister Shinzo Abe of Japan met on the sidelines of an economic forum in the Russian port city of Vladivostok.
Speaking after the talks, Putin reiterated that the crisis should be resolved only by political means.
"First of all, there is a need to ease tensions and then build a dialogue between the interested parties, as stipulated by the Russian-Chinese road map aimed at gradually resolving the issue," he told reporters.
"We completely agreed that North Korea's nuclear test is a serious threat to the peace and stability of Korean Peninsula as well as the region, and a grave challenge to the global nonproliferation regime," Abe said.
Putin also said he and Abe discussed the prospect of a long-delayed peace treaty formally ending World War II hostilities.
A dispute over a group of islands that Russia seized at the end of the war -- called the Southern Kuriles by Russia and the Northern Territories by Japan -- has strained ties and has kept the two countries from signing such a treaty.
Ahead of the talks with Putin, Abe said the international community "must make North Korea immediately and fully comply with all relevant UN Security Council resolutions and abandon all its nuclear and ballistic missile programs in a complete, verifiable and irreversible manner."
Earlier, Abe and South Korean President Moon Jae-in met in Vladivostok and agreed to "further increase sanctions and pressures against the North as much as possible," according to Moon's spokesman Yoon Young-chan.
The two leaders felt Russian and Chinese involvement was paramount and agreed to work toward that goal, Yoon also said.
North Korea’s sixth nuclear bomb test on September 3 -- its most powerful to date -- has triggered global condemnation, but Putin has brushed off calls for tighter sanctions, pushing for negotiations instead.
Speaking on September 7, the Russian president said that Pyongyang would not end its nuclear and missile programs because it views them as its only means for self-defense.
Putin once again said that imposing tighter sanctions was not the way forward because Pyongyang can’t be intimidated.
"It's impossible to scare them," he said.
Pyongyang is already under highly restrictive sanctions imposed by the UN and aimed at forcing it to curtail its weapons programs.
It was not clear whether China, North Korea's main ally, would support the tough new moves against Pyongyang.
"Given the new developments on the Korean Peninsula, China agrees that the UN Security Council should respond further by taking necessary measures," Chinese Foreign Minister Wang Yi said on September 7.
But he added that "sanctions and pressure are only half of the key to resolving the issue. The other half is dialogue and negotiation."
In the Estonian capital, Tallinn, EU foreign policy chief Federica Mogherini said on September 7 that she will propose considering "new autonomous EU sanctions on North Korea."
NATO Secretary-General Jens Stoltenberg said that North Korea's "behavior is a global threat and requires a global response, a united global response."
A draft U.S. proposal circulated to the UN Security Council members calls for a total ban on supplying a range of oil products to North Korea and on its textile export industry.
It also suggests freezing the assets of the reclusive country's government and its leader, Kim Jong Un, as well as banning him and other officials from travelling.
North Korean laborers would also be banned from working abroad, mainly in Russia's Far East and China.
North Korea pledged to take "powerful counter measures" to respond to U.S. pressure or any new sanctions against it.
A statement by the North Korean delegation to Vladivostok also accused South Korea and Japan of using the Russian forum to play "dirty politics."
Also on September 7, the four remaining launchers of the U.S. antimissile Terminal High Altitude Area Defense (THAAD) system arrived at a base south of Seoul, joining two launchers that have been operational at the site since May.
The rollout was "temporarily" completed, the South Korean Defense Ministry said, adding it was necessary to counter increased threats from North Korea.
The deployment has been strongly opposed by Russia and China.