WASHINGTON (REUTERS) - Russia's war in Ukraine has worsened the "already dire" food insecurity situation facing the world, with price and supply shocks adding to global inflationary pressures, US Treasury Secretary Janet Yellen told a high-level panel on Tuesday (April 19).

Even before the war, over 800 million people - or 10 per cent of the global population - were suffering from chronic food insecurity, Ms Yellen said, citing early estimates showing that higher food prices alone could push at least 10 million more people worldwide into poverty.

Ms Yellen told the panel that countries should avoid export restrictions that could further increase prices, while acting to support vulnerable populations and smallholder farmers.

"I want to be clear: Russia's actions are responsible for this," Ms Yellen said, adding that the United States was working urgently with partners and allies to "help mitigate the effects of Russia's reckless war on the world's most vulnerable".

Russia calls its actions a "special military operation".

Ms Yellen underscored Washington's commitment to authorising essential humanitarian aid and ensuring the availability of food and agricultural commodities to benefit people around the world, even as it continued escalating its sanctions and other economic measures against Russia.

She said it was also critical to strengthen longer-term resilience, and called on the international financial institutions to help mitigate the global fertiliser shortage and smooth supply chain disruptions for food and critical supplies.

She said they could increase investments in agricultural capacity and resilience to boost domestic food production.