Ukraine's military has launched a string of attacks on Russian oil tankers overnight, striking 12 vessels as tensions between the two nations reach a boiling point. The strikes, which targeted tankers in the Black Sea and Sea of Azov, come as Russian President Vladimir Putin grapples with a nationwide fuel shortage that has left motorists struggling to find petrol. In a surprise move, Ukrainian President Volodymyr Zelensky announced a significant escalation of the conflict over the fuel shortage, saying that his country would no longer 'hesitate' to target key infrastructure. 'We have been patient for too long, but now it is time to take action,' Mr Zelensky said in a televised address on Tuesday. 'We will not wait until our economy is brought to its knees.'