US President-elect Joe Biden has unveiled officials for six important posts, as he prepares to take office.
"America is back", he said, and "ready to lead the world, not retreat from it".
If confirmed, Avril Haines will be the first female director of national intelligence and Alejandro Mayorkas the first Latino homeland security boss.
Donald Trump has agreed transition moves must start and Mr Biden will now get a top secret intelligence brief.
However, the sitting president still refuses to admit defeat, repeating unsubstantiated claims that the 3 November vote was "rigged".
As well as getting the Presidential Daily Brief- an update on international threats and developments - Mr Biden can now access key government officials and millions of dollars in funds as he prepares to take over on 20 January.
On Tuesday, Governor Tom Wolf said he had certified Mr Biden's victory in Pennsylvania, a key swing state. Another, Michigan, certified the same outcome on Monday.
Speaking in Wilmington, Delaware, the president-elect highlighted the need to rebuild alliances, as well as tackling coronavirus and climate change.
World leaders, he suggested, were "looking forward to the United States reasserting its historic role as a global leader over the Pacific, as well as the Atlantic, all across the world".
Speaking to NBC News, he said: "This president, President Trump, has changed the landscape. It's become America first, America alone. We find ourselves in a position where our alliances are being frayed."
Mr Biden also told reporters he had discussed the Irish border issue with UK Prime Minister Boris Johnson and other leaders.
Mr Biden, who has Irish heritage, said he was against a guarded border, arguing it must be kept open: "The idea of having the border north and south once again being closed, it's just not right."
Speaking to NBC, Mr Biden said outreach from the White House had been "sincere", not "begrudging".
There were, he said, plans for him to meet the Covid task force in the White House about vaccine distribution and access.
Barack Obama's former vice-president said that his time in office would not be a "third Obama term" because "we face a totally different world than we faced in the Obama-Biden administration".
Source: BBC