US Treasury secretary Janet Yellen has stepped up pressure on the leadership of the World Bank by urging it to “quickly” put in place reforms to free up more money to address climate change among other global challenges.

The US is the largest shareholder in the international finance institution that provides funding for developing countries and has pushed for an overhaul along with several other major shareholders including Germany.

Speaking in Washington on Thursday, less than a fortnight after a trip to three African countries, Yellen focused on her concerns about the bank. It should “expand its vision to include addressing global challenges” and help lower costs for countries needing funds to do so, as well as to engage in “stronger” mobilisation of private finance, she said.