July 6 (UPI) -- President Donald Trump, speaking on Thursday in Warsaw, Poland, said he was considering "some pretty severe things" to respond to the North Korean nuclear threat.
Trump made the comment during a press conference after holding a meeting with Polish President Andrzej Duda. Pyongyang on Tuesday said it conducted a successful intercontinental ballistic missile test.
"We'll see what happens -- I don't like to talk about what we have planned -- but I have some pretty severe things that we're thinking about," Trump said during the press conference. "They are behaving in a very, very serious manner, and something will have to be done about it."
Trump said the United States and the world must "demonstrate that there are consequences for their very, very bad behavior."
On the matter of Russia's interference in the 2016 U.S. election, Trump suggested he was not yet convinced Moscow was solely responsible.
"I think it was Russia, and it could have been other people in other countries," Trump said. "Nobody really knows."
Trump and his foreign delegation reached Warsaw on Wednesday evening. On Thursday morning he left the Warsaw Marriot where he stayed to travel to the Polish presidential palace to hold a closed-door meeting with Duda.
Later on Thursday, Trump is expected to deliver a speech in Krasinski Square, where a monument memorializes the Warsaw Uprising against the Nazis in 1944. According to excerpts of the speech provided by the White House, Trump will say that "the fundamental question of our time is whether the West has the will to survive."
"I am here today not just to visit an old ally, but to hold it up as an example for others who seek freedom and who wish to summon the courage and the will to defend our civilization," Trump is expected to say in his speech. "We must stand united against these shared enemies to strip them of their territory, their funding, their networks, and any form of ideological support ... While we will always welcome new citizens who share our values and love our people, our borders will always be closed to terrorism and extremism."
After his speech on Thursday, Trump will head to Hamburg, Germany, for a G20 economic summit, which meets Friday. He is also expected to meet with Russian President Vladimir Putin.
Kremlin officials said the meeting between Trump and Putin will be a full bilateral meeting instead of a brief side meeting amid the G20 summit.