WASHINGTON - Tensions are quickly rising between the United States and North Korea, which has ramped up pressure as it demands concessions by President Donald Trump's administration by the end of the year.

The United States called a UN Security Council meeting for Wednesday on North Korea's series of rocket launches, the latest return to antagonism as diplomacy languishes.

Monday's announcement came two days after North Korea claimed to have carried out a "very important" but otherwise unspecified test, in a hint that it may have further actions in store.

Trump has met three times with North Korean leader Kim Jong Un to discuss Pyongyang's nuclear program, describing him a friend and hailing the comparative calm achieved since 2017 when fears were growing of all-out war.

But North Korea is seeking a comprehensive deal that includes sanctions relief, especially with Trump heading next year into a potentially difficult re-election fight.

Trump said Saturday that Kim has "too much to lose, everything actually, if he acts in a hostile way" and said he would be "surprised if North Korea acted hostilely."

In a rare personal attack on Trump since the start of diplomacy, Kim Yong Chol, a longtime aide to the top leader, called the US president a "heedless and erratic old man" and condemned his "odd words and expression."

If Trump is not "astonished" by North Korea's response, "we will be irritated," Kim said in a statement quoted by the official Korean Central News Agency.

The United States, which holds this month's presidency of the Security Council, called Wednesday's meeting to give a "comprehensive update" on the Korean peninsula and postponed a session on the authoritarian state's human rights record, a State Department spokesperson said.

The meeting will look at "recent missile launches and the possibility of a DPRK provocation," the spokesperson said, referring to the North by its official name, the Democratic People's Republic of Korea.

The Security Council also met last week behind closed doors at the best of European nations to condemn 13 missile tests by North Korea. -AFP