North Korea conducted its fifth nuclear test on September 9 past year, and then carried out a sixth a week ago, saying it was a hydrogen bomb that could be fitted onto a missile - prompting global condemnation and calls for further sanctions.
The U.S. officially asked the U.N. Security Council to vote on a draft sanctions resolution Monday.
"To the degree that North Korea knows that the worldwide community is going to punish it for conducting its sixth nuclear test - or try to punish it, at any rate - there is no incentive not to do something else provocative on September 9".
North Korea will celebrate 69th year of its founding.
North Korea says it needs its weapons to protect itself from USA aggression and regularly threatens to destroy the United States.
U.S. Secretary of State, Rex Tillerson, said on Thursday that if North Korea wants a response after a nuclear attack, "there will be one".
"Military action would certainly be an option", Mr Trump said at a White House news conference.
On the possibility of North Korea staging a war, 58 percent said there is no likelihood while 37 percent said it could be possible.
South Korea President Moon Jae-in met with Japanese Prime Minister Shinzo Abe Thursday morning in Vladivostok where they're attending the Eastern Economic Forum, hosted by Russian President Vladimir Putin.
On Thursday and Friday, the US and South Korea are set to conduct a joint anti-submarine drill, Yonhap news agency reported.
"There is nothing more foolish than thinking we, a strong nuclear state, will endure this evil pressure aimed at overthrowing our state", the North's official news agency said in a commentary.
Six police officers and 32 other people were injured, none seriously, in the clashes, said a fire department official in Seongju.
President Moon has repeatedly stated his opposition to military conflict on the Korean Peninsula, preferring instead to hold talks with the North.
Moon, who was elected in May after a corruption scandal engulfed his predecessor, Park Guen-hye, bringing about her impeachment, still enjoys great popularity among South Koreans.
Kang Myung-do defected from North Korea in the mid-1990s.
Kim Jong-un has threatened to fire missiles at the island of Guam, where the USA has its foothold in the Pacific Ocean - a key strategic location.