Russian President Vladimir Putin on Wednesday signed constitutional laws to make the four Ukrainian regions parts of Russia, reported Sputnik News. The four regions – Donetsk, Luhansk, Kherson and Zaporizhzhia – were annexed by Russia last week.

The announcement of annexations was based on the results of referendums Russia held in the four regions, which together make up for 15% of Ukraine’s territory. Referendums were held in the four regions from September 23 to September 27.

Putin signed the laws after they were approved by both chambers of the Russian Parliament – the State Duma and Federation Council, reported the Associated Press.

Ukrainian officials had alleged that residents in the four regions were banned from leaving until the four-day vote was over as armed groups went into homes and threatened them if they did not participate, reported Reuters.

Soon after Putin’s announcement last week, Ukraine President Volodymyr Zelenskyy had said his country will formally apply for a fast-track membership of the North Atlantic Treaty Organisation, or NATO. Zelenskyy, in his decree released on Tuesday, said that holding negotiations with Putin has become impossible after his decision to take over the four regions of Ukraine, reported AP.

Meanwhile, on October 1, India had abstained from voting on a draft resolution tabled in the United Nations to condemn Russia’s “illegal referenda” and annexation of four Ukrainian territories.

Russia had launched an invasion of Ukraine on February 24. The Kremlin had described its actions as a “special operation” to demilitarise and “de-Nazify” Ukraine. However, Kyiv and several Western nations said that this is a baseless pretext for a war of choice by Putin.