(Adds Mattis call with South Korean minister, U.S. move to obtain North Korean funds from eight banks)

By Jeff Mason and Roberta Rampton

WARSAW, July 6 (Reuters) - U.S. President Donald Trump vowed on Thursday to confront North Korea "very strongly" following its latest missile test and urged nations to show Pyongyang there would be consequences for its weapons program.

North Korea on Tuesday test launched an intercontinental ballistic missile that some experts believe has the range to reach Alaska and Hawaii and perhaps the U.S. Pacific Northwest. North Korea said it could carry a large nuclear warhead.

Speaking at a news conference with Polish President Andrzej Duda, Trump said North Korea was "a threat, and we will confront it very strongly".

He said the United States was considering "severe things" for North Korea, but that he would not draw a "red line" of the kind that his predecessor, Barack Obama, had drawn but not enforced on the use of chemical weapons in Syria.

Trump added: "They are behaving in a very, very dangerous manner and something will have to be done."

U.S. Defense Secretary Jim Mattis said the missile test in itself did not bring the parties closer to a war and stressed that America's focus was on diplomatic efforts to pressure Pyongyang.

"We stand ready to provide (military) options if they are necessary. But this is a purely diplomatically led (effort)," Mattis told a small group of reporters at the Pentagon.

"Diplomacy has not failed. ... Diplomatic efforts remain under way as we speak."

Mattis spoke by phone with South Korean Defense Minister Han Min-koo on Thursday, reaffirming Washington's commitment to the U.S.-South Korea alliance and promising "the full range of U.S. capabilities." He spoke with his Japanese counterpart on Wednesday.

The issue presents Trump, who took office in January, with perhaps his biggest foreign policy challenge and has put pressure on his relationship with Chinese President Xi Jinping, whom the Republican president had pressed without success to rein in Pyongyang.

China called on Thursday for restraint and made clear it did not want to be targeted by U.S. sanctions.

Chinese Vice Finance Minister Zhu Guangyao said that while China would implement relevant U.N. resolutions, "the U.S. should not use their domestic laws as excuses to levy sanctions against Chinese financial institutions".

Late on Thursday, court filings made public disclosed that U.S. authorities were trying to seize millions of dollars from companies that deal with North Korea, including the country's military, from eight large international banks.