Farm ministers from the Group of 20 major economies on Tuesday vowed to oppose any restrictive measures that would threaten food security and disrupt global food supply chains amid the coronavirus pandemic.

More than a dozen countries, including Russia, Cambodia and Thailand, have imposed export restrictions on agricultural products and other supplies as of Monday, according to the Japanese farm ministry. The restrictions center on grain.

Some countries are apparently concerned that the spread of the pandemic, which has triggered governments around the world to implement various types of lockdown measures, could affect agricultural systems and cause nations to prioritize their domestic markets.