The US and its allies are not going to be intimidated by Russian President Vladimir Putin and his threats, said President Joe Biden on Friday after Moscow's annexation of Ukrainian territories.

“He is not going to scare us and he's not going to intimidate us,” Biden said in his address on Hurricane Ian at White House.

Biden said Putin's actions are a sign that he is struggling and slammed the “sham” referendums in Ukraine, adding that the US is “never going to recognize this and quite frankly the world is never going to recognize this either.”

“He can't seize his neighbor's territory and get away with it,” he said.

Putin earlier on Friday announced the annexation of the four Ukrainian regions – Donetsk, Luhansk, Zaporizhzhia and Kherson – in violation of international law following highly disputed referendums that have been denounced by the West and its allies as a “cynical land grab.”

The territories amount to more than 90,000 square kilometers (34,749 square miles) or nearly 15% of Ukraine's total area.

Biden said Russians are going to stay the course but the US will also be continuing to provide military equipment so that Ukraine can defend itself and its territory.

“America is fully prepared with our NATO allies to defend every single inch of NATO territory ... So, Mr. Putin, don't misunderstand what I'm saying. Every inch,” the US president added. (Anadolu Agency)