US Treasury Secretary Janet Yellen has signalled a stronger engagement on issues from climate change to human rights to tax evasion, pledging to restore America's economic leadership.

"America first must never mean America alone," she said in her first major speech on its overseas economic policy.

Ms Yellen is also keen for greater global co-operation, rolling back Donald Trump's protectionist policies.

She also raised the issue of a global corporate tax rate.

"Over the last four years, we have seen first hand what happens when America steps back from the global stage," Ms Yellen said pointing to a reversal of Mr Trump's international economic policies.

The US "isolated ourselves and retreated from the international order that we created," she added.

Marking an American return to the global stage, she said: "For in today's world, no country alone can suitably provide a strong and sustainable economy for its people."

As part of the increased global leadership role for the US, Ms Yellen outlined the case for a harmonised corporate tax rate across the world's major economies.

"Together we can use a global minimum tax to make sure the global economy thrives based on a more level playing field in the taxation of multinational corporations, and spurs innovation, growth and prosperity," Yellen said during an online interview with the Chicago Council on Global Affairs.

Corporate taxes are one of the revenue-raising proposals for President Joe Biden's $2.25 trillion (£1.62 trillion) package of infrastructure and other spending announced last week.

Ms Yellen wants to halt what she described as an international "race to the bottom" by countries competing to lure corporations with lower taxes.
China threat

While she said the Biden-Harris administration is committed to helping "make the world economy stronger" she added that it also wanted to "advance American interests".

Ms Yellen hinted at a softer approach towards the growing threat of China, which the US is still embroiled in a trade war with.

"Our economic relationship with China, like our broader relationship with China, will be competitive where it should be, collaborative where it can be, and adversarial where it must be," she added.