But Putin, speaking in China on Tuesday, cautioned against "military hysteria" and said that the only way to resolve the crisis was through diplomacy.
He warned that North Korean leader Kim Jong Un has calculated that the survival of his regime depends on its development of nuclear weapons. Kim had seen how western intervention in Iraq had ended in the overthrow of Saddam Hussein after which the country was ravaged by war, Putin warned, and Kim was determined not to suffer the same fate.
"Saddam Hussein rejected the production of weapons of mass destruction, but even under that pretense, he was destroyed and members of his family were killed," Putin said.
"The country was demolished and Saddam Hussein was hanged. Everyone knows that and everyone in North Korea knows that."
On Monday, US Ambassador to the United Nations Nikki Haley said Kim was "begging for war"
and urged the UN Security Council to adopt the strongest sanctions measures possible to stop Pyongyang's nuclear program.
But speaking at the closure of the BRICs summit in Beijing -- which hosted the leaders of Brazil, India, China and South Africa -- Putin said that while Russia condemned North Korea's latest actions, imposing any kind of sanctions would be "useless and ineffective." Kim would rather starve his people than see his regime overthrown, he said.
"They will eat grass but they will not turn away from the path that will provide for their security," he said.
The latest escalation of the crisis came on Sunday when Pyongyang announced it had conducted a sixth nuclear test, which it claimed was of a hydrogen bomb. The claim has not been independently verified, but seismological data indicated that the weapon was the most powerful ever to be detonated by Pyongyang.
North Korea claims it now has the capability of mounting a thermonuclear weapon on a long-range missile capable of striking the United States.
Weapons experts say it's almost impossible to verify if the warhead and missile could be successfully paired unless North Korea were to fire a nuclear-tipped ICBM.
North Korea has test-fired a number of missiles this summer
, including two long-range ones in July and an intermediate-range one in August that overflew the Japanese island of Hokkaido. South Korea has claimed that the North is making preparations for another ICBM test.
Putin said it was clear that Pyongyang already had a nuclear capability -- and in any case, no missile defense system could offer adequate protection against conventional long-range artillery.
"We know that North Korea has nukes, we also know that North Korea has long-range artillery and it has other types of weapons and there are no weapons against long-range artillery -- and these weapons can be difficult to locate.
"So we think that this military hysteria will not lead to good results. It could lead to global catastrophe with lots of victims."
In response to the latest tests, the South Korean Navy announced Tuesday it conducted live-fire drills off the east coast of the Korean Peninsula to check its "immediate operational readiness" after the country's air force and army conducted their own joint drills. It had already mounted a huge show of military force on Monday.
South Korean President Moon Jae-in spoke with US President Donald Trump on Monday and agreed to lift current restrictions on the payload weight of South Korea's ballistic missiles, according to a South Korean presidential spokesman.