By Steve Schifferes BBC News Online in Washington

US Secretary of State Colin Powell testimony to the United Nations has played well to one of his crucial audiences - senators on Capitol Hill.

Early evidence also suggests that it has played equally well with the American public, who now back US action against Saddam Hussein by around 60% - 40%.

There has been some shift in attitude Colin Powell US Secretary of State

Now the US is determined to keep up the pressure on members of the Security Council to gain endorsement from the international community for that action.

Secretary Powell told the Senate Foreign Relations committee that he had met privately with all 13 members of the Security Council after his speech on Wednesday - all except for Britain, whom he did not believe needed convincing.

And he said that he was hopeful that in private, many nations were more sympathetic to the US position than they sounded in their prepared statements, which were written before his presentation.

The president should stop downplaying this threat (North Korea) and start paying more attention to it Senate Minority leader Tom Daschle

"There was some shift in attitude," he said.

The message was reinforced by President Bush later in the day, when he said that the US would welcome a second UN resolution if it showed a strengthened resolve.

Warnings

The US secretary of state warned that there were many risks to the course of action that the US was moving towards.

He said that there was a heightened risk of terrorism, especially in the Middle East.

And he admitted that there were big political risks for those European allies of the United States who were supporting its position on Iraq, which was unpopular among their publics.

But he said that the risks of not acting - and the fear that US would ultimately become the victim of terrorists armed with weapons of mass destruction - had to outweigh these worries.

And later in the day the State Department issued a general warning to all US citizens abroad to be especially vigilant over the next few months.

Changing tack

Mr Powell's performance at the UN drew praise from across the political spectrum, with several senators who had wanted to give the inspectors more time saying he had made a powerful case.

Senator Dick Lugar, chairman of the Foreign Relations Committee, suggested that Mr Powell had "won over almost every senator" on the fact that Iraq was in breach of the UN resolution.

Instead, attention was focused on whether the administration had prepared properly for the post-Saddam era, and had a long-term commitment to rebuild democracy in Iraq.

The secretary of state alluded to plans, but did not spell them out.

However, he said that a victory against Saddam could have wider consequences.

"There is also the possibility that success could fundamentally reshape that region in a positive way that will enhance US interests," he said.

He added that the US was still committed to the Middle East peace process, and was planning to put forward its "road map" proposals shortly which would propose a Palestinian state.

But the Palestinians would need to reform their institutions to make them more democratic and credible first, he added.

Korea

Much attention of the Democratic Senators was focused on North Korea, where the government has said it was restarting its nuclear weapons programme.

Senate Minority leader Tom Daschle said that "the president should stop downplaying this threat and start paying more attention to it".

Mr Powell denied that the administration had ignored this problem, but did acknowledge that it knew about the clandestine programme by the summer of 2002.

Ranking Democrat, Senator Joe Biden said that he was "concerned that our understandable focus on Iraq at this time is taking focus off what I believe to be an equally, if not more immediate threat to US interest and those of our allies."

"We don't have the luxury of dealing with one issue," Mr Powell replied.

And he angrily denied suggestions by California Senator Barbara Boxer that the US had a policy of "designed neglect" in other areas of foreign policy.

All in all, it was another impressive performance for Mr Powell before a friendly audience - but also a warning of the difficult issues on the agenda to come.