President Biden and leaders of the Group of 7 nations on Friday condemned Russia’s hastily called referendums in occupied parts of Ukraine, a possible prelude to the annexation of those territories, calling the votes a flagrant violation of international law.

“These sham referenda initiated today by Russia and its proxies have no legal effect or legitimacy, as demonstrated by Russia’s hasty methods of organisation, which in no way respect democratic norms, and its blatant intimidation of local populations,” the leaders of the group, which includes the US, Britain and other western powers, said in a statement released on Friday afternoon.

“These referenda in areas that have been forcibly put under Russia’s temporary control in no way represent a legitimate expression of the will of the Ukrainian people, who have consistently resisted Russian efforts to change borders by force,” the leaders continued.

“We will never recognise these referenda which appear to be a step toward Russian annexation and we will never recognise a purported annexation if it occurs.”

The White House press secretary, Karine Jean-Pierre, told reporters on Friday that the Biden administration was “prepared to impose additional swift and severe economic costs on Russia along with our allies and partners in response to these actions if they move forward with annexation”.