Seventy-five Ukrainian crop storage facilities have been damaged since Russia invaded in February, a US government-backed study has found.

The vast majority of them are near the country’s ports or railroads.

Conflict Observatory, a group analysing potential Russian war crimes, used satellite imagery to evaluate facilities in Ukraine’s east and central. It found that at least 60 of the 75 damaged storage facilities were either at ports or near railroads — some directly next to railroad tracks at port facilities.

“Further analysis is required to draw any definitive conclusions about why the overwhelming majority of damage-affected facilities identified by this assessment are co-located with critical transportation infrastructure,” the Yale School of Public Health and a US Department of Energy lab said in the report.

“Regardless, the finding is significant.”

The two suggested that more analysis was necessary to determine if the damage was inflicted indiscriminately or intentionally and if the attacks were carried out at the behest of Russian commanders.

Ukraine is a major exporter of grain and the Russian invasion raised fears of a global food crisis.

Earlier in the summer, a grain export corridor was established and on 1 August the first ships carrying the cargoes left Odesa.

The agreement has seen more than 2.7m tonnes of grain exported, according to US government figures.

Conflict Observatory, of which the Yale School of Public Health is a member, said facilities in Odesa have been spared. The majority of the damage has taken place in Russian-controlled Donetsk and Zaporizhzhia, and partially-controlled Mykolaiv, where Bunge reported damage to its facilities in June.

Recently, Russian President Vladimir Putin has said he would like to renegotiate the deal, hashed out between Turkey, Ukraine, Russia and the United Nations, ostensibly because many of the exports are headed to the European Union instead of developing countries.

The US State Department said Russia’s actions were imperilling the health and well-being of millions across the world.

“Russia has exacerbated a global food security crisis, contributed to significant spikes in the cost of wheat, and forced a scramble to keep hungry and vulnerable populations fed,” a department spokesperson said in a statement.

“The United States will continue to firmly stand with Ukraine as it defends its freedom, for the sake of its own people and of people across the globe who rely on the harvests from Ukraine’s farmlands.”