UNITED NATIONS, April 11 (Xinhua) -- Swedish ambassador to the United Nations Olof Skoog on Wednesday warned against military action against Syria after U.S. President Donald Trump threatened to launch a missile attack.

"What the Syrian people want and need is peace and justice, not further military escalation or impunity. Let that also be a response to planned military intervention etc.," Skoog told reporters at UN Headquarters in New York.

"Whatever happens now has to be in line with international law," he said before walking into the Security Council chamber for a meeting on Mali.

Skoog refused to comment on a tweet by Trump early Wednesday morning.

"Russia vows to shoot down any and all missiles fired at Syria. Get ready Russia, because they will be coming, nice and new and 'smart!' You shouldn't be partners with a Gas Killing Animal who kills his people and enjoys it!" Trump tweeted.

Asked whether such military action against Syria requires Security Council authorization, Skoog said: "The (UN) Charter is very clear about military intervention."

Skoog expressed disappointment at the failure of the Security Council to adopt any resolution with regard to chemical weapons use in Syria. "The Security Council failed to shoulder its responsibility yesterday," he said.

Sweden supported the U.S. draft on a new investigative mechanism for chemical weapons use in Syria and thought it was the best way forward, he said. But the draft, which won the support of 12 of the 15 Security Council members, was vetoed by Russia.

A competing text prepared by Russia had no chance of adoption at all, he said.

Having anticipated the deadlock, Sweden on Monday circulated "a very credible, very assertive compromise resolution" in order to find common ground in the Security Council for an outcome in support of an investigation by the Organization for the Prohibition of Chemical Weapons (OPCW) into the alleged chemical attack in Douma. Russia amended the Swedish work and tabled it as a third draft resolution for vote on Tuesday.

However, some Security Council members were not ready to engage -- for political reasons that have nothing to do with the substance of the draft, said Skoog.

The third text failed to be adopted as it won only five positive votes.

The Fact-Find Mission of the OPCW is going into Syria to probe the Douma attack. "There will be an investigation. The problem is that there is no follow-on, which is to establish responsibility, guilt, accountability. That has to be worked out," said Skoog.

The Joint Investigative Mechanism between the OPCW and the United Nations, which was set up by the Security Council for the purpose of accountability attribution for chemical weapons use in Syria, ceased to be in November 2017 after Russia blocked the renewal of its mandate.