South Korea said it was talking to Washington about deploying aircraft carriers and strategic bombers to the Korean peninsula.
U.S. President Donald Trump held calls with foreign leaders, including South Korean President Moon Jae-in and German Chancellor Angela Merkel, and the White House declared that "all options to address the North Korean threat are on the table."
Moon and Trump agreed in a telephone call to scrap a warhead weight limit on South Korea's missiles, South Korea's presidential office said, enabling it to strike North Korea with greater force in the event of a military conflict. The White House said Trump gave "in-principle approval" to the move.
U.S. Ambassador to the United Nations Nikki Haley said North Korea's Kim Jong Un was "begging for war" and urged the 15-member U.N. Security Council to impose the "strongest possible" sanctions to deter him.
"War is never something the United States wants. We don't want it now. But our country's patience is not unlimited. We will defend our allies and our territory," Haley said.
"The United States will look at every country that does business with North Korea as a country that is giving aid to their reckless and dangerous nuclear intentions," she said.
Haley said the United States will circulate a new Security Council resolution on North Korea this week and wants a vote on it next Monday.
China, a top trading partner with North Korea, and Russia called for a peaceful resolution to the crisis.
"China will never allow chaos and war on the (Korean) Peninsula," said Liu Jieyi, the Chinese ambassador to the United Nations, urging North Korea to stop taking actions that were "wrong" and not in its own interests.
Russia said peace in the region was in jeopardy.
"Sanctions alone will not help solve the issue," Russia's U.N. Ambassador Vassily Nebenzia said.
North Korea has been under U.N. sanctions since 2006 over its ballistic missile and nuclear programs. Typically, China and Russia only view a test of a long-range missile or a nuclear weapon as a trigger for further possible U.N. sanctions.
Officials said activity around missile launch sites suggested North Korea planned more missile tests.
"We have continued to see signs of possibly more ballistic missile launches. We also forecastNorth Korea could fire an intercontinental ballistic missile," Jang Kyoung-soo, acting deputy minister of national defense policy, told a parliament hearing on Monday.
North Korea tested two ICBMs in July that could fly about 10,000 km (6,200 miles), putting many parts of the U.S. mainland within range and prompting a new round of tough international sanctions.
Enter a name and e-mail address and we will e-mail this website link too them.