WASHINGTON — New World Bank President Jim Yong Kim warned Monday that the eurozone crisis poses a deep threat to the global economy as he launched into his first day leading the development lender.

The Korean-American physician, who won a contest against developing country candidates in April to run the bank, said the world's economy "remains highly vulnerable."

The World Bank has "an economic and moral imperative to help address risks to global growth, no matter where they emerge," he said.

"A strong global economy benefits all countries; a weak global economy makes all countries vulnerable.

"It is urgent that European countries take all necessary measures to restore stability because their actions will impact growth in all regions of the world.

Kim -- a global health expert who contrasts with the bankers and diplomats that Washington has named to run the bank in the past -- pledged to stick to the mission of helping the poorest countries get on their feet.

He gave no hint of any changes to the work of his predecessor, Robert Zoellick.

"I'm humbled and inspired to take over today as president," Kim said at the doorstep of the Washington-based global development lender Monday morning.

"I can't wait to get started."

"I've spent most of my adult life working in some of the poorest communities in the world."

He said the bank will continue to operate "with innovation, with analytic rigor and with great passion, working in partnership with governments, with civil society organizations, with the private sector, and most importantly with the people living in poverty we aspire to serve."

But it was "a pivotal moment" with the eurozone crisis and economic slowdown in the largest countries impacting small, vulnerable economies around the world.

"I will work with our clients and partners to ensure that we are creating a new economic firewall: one that protects people in developing countries against shocks."

"I know from my work in poor communities around the world that, when a crisis hits, and no safety net is in place, the effects can be devastating."

He takes over a sprawling institution of 9,000 economists and policy specialists, which made loans, grants and guarantees of $52.6 billion in the year to June 30.

Unlike the bankers, diplomats and economists who have run the World Bank in the past, Kim brings a background in medicine and a record of developing programs to fight diseases like HIV/AIDS and tuberculosis in poor countries.

His nomination to the post by President Barack Obama surprised many; his last job was as head of Dartmouth College, a small but prestigious university.

He beat out two prominent economists from developing countries in the first time since the bank was created in 1944 that Washington's nominee was challenged.

But he has given little hint about any new directions he might plot for the bank, saying only that it remains "passionate about the twin aims of boosting prosperity and eradicating poverty."

Kim needs to "take fast action to protect developing countries from Europe's debt crisis," said Oxfam Great Britain's chief executive Barbara Stocking in a statement.

"The Bank has an obligation to urgently ratchet up efforts in countries that depleted their resources defending themselves during the last financial crisis."

The 52-year-old Kim was born in South Korea and raised in the rural US Midwest. His dentist father taught at Iowa University, and his mother had a doctorate in philosophy.

Kim -- who goes by the name Jim Kim -- attended Brown University and then Harvard Medical School, and following that earned a Harvard doctorate in anthropology.

He replaces Zoellick, a former US diplomat who took over in 2007 following the resignation of Paul Wolfowitz, another diplomat whose tenure at the bank was cut short by scandal and conflict with bank staff.

Zoellick restored the institution's image and helped it adjust quickly to the financial crisis that erupted in the United States as he took over, as it sent shock waves through the global economy.