In early May, British troops landed at San Carlos on the western side of East Falkland, and from there moved overland towards the islands' capital of Stanley. To support the advance, logistical supplies were ferried to the troops by helicopter from San Carlos.[2] The Argentine forces occupying Stanley were supplied throughout the war by C-130 Hercules aircraft from the Argentine mainland. These "milk-runs", as the British termed them, were a source of concern to the Royal Navy, and various attempts were made to intercept them.[5][6]