At 11:00 p.m. on 1 April 1982, the Argentine destroyer Santasima Trinidad landed a small Buzo Tactico (BT, Special Forces) detachment on the south shore of East Falkland Island’s Cape Pembroke. They secured a landing zone on Mullet Creek and reported the “all clear” to the Argentine Task Force commander, Rear Adm. Jorge Allara, who ordered the assault to begin. Five and a half hours later, two more BT platoons and an additional reconnaissance element were on the island. Operation Rosario was underway; its purpose was to assert Argentine control over the islands, in dispute since 1833.
The two platoons landed at the Mullet Creek Landing Zone and pushed north to assault the abandoned Royal Marine barracks at Moody Brook while the initial BT detachment moved toward Port Stanley. The BT reconnaissance element departed the submerged submarine Sante Fe and reconnoitered York Bay, reporting the absence of beach defenses and defenders. At 6:00 a.m. the LST Cabo San Antonio dropped its ramp for the 2nd Argentine Marine Battalion’s 20 amphibious tractors (LVTPs) to take their troops ashore at York Bay.
Meanwhile, the helicopters from the Argentinian icebreaker Almirante Irizar landed another BT detachment east of the airfield. By 6:30 a.m., the 20 Royal Marines defending the airfield were driven off, retreating toward Port Stanley. By 9:30 a.m., with ammunition running out, the Falklands’ Royal Governor, Rex Hunt, ordered the Royal Marines and Falklands’ Home Defense Force to surrender.