It was fought mainly between an assaulting British force consisting of Royal Marines of 45 Commando and an Argentine Company drawn from 4th Infantry Regiment (Regimiento de Infantería 4 or RI 4).

Major Óscar Ramón Jaimet's B Company of the 6th Mechanized Infantry Regiment (Regimiento de Infantería Mecanizado 6 RI Mec 6), acting as the local reserve, occupied the saddle between Two Sisters and Mount Longdon.

Beginning on 1 June, the 4th Infantry Regiment, stationed on Two Sisters and Mount Harriet, was authorized by its commanding officer, Lieutenant Colonel Diego Soria, to utilise their cold-weather ration packs.

[12]On 4 June, the three rifle companies of 45 CDO advanced on Bluff Cove Peak, on the lower slopes of Mount Kent, and were able to occupy the feature without opposition and were met by patrols from the Special Air Service (SAS).

Captain Andrés Ferrero's patrol, consisting of the 3rd Assault Section of the 602 Commando Company, advanced to the base of Mount Kent but was soon pinned down by sustained machine gun and mortar fire.

Sub-Lieutenant Llambías-Pravaz's platoon was later credited with the destruction of Harrier XZ963 flown by Squadron Leader Jerry Pook[17][18] while others claim the British fighter-bomber ran into fire from a battery of 35 mm Oerlikons under the command of 2nd Lieutenant Roberto Enrique Ferre[19][20] of the 601st Anti-Aircraft Artillery Group.

[21] A heavy mist hung over the Murrell River area, which assisted the 45 Commando Recce Troop to reach and sometimes penetrate the Argentine 3rd Platoon position under Sub-Lieutenant Marcelo Llambías-Pravaz.

[7]], and all we had was one bloke with a flesh wound.For his patrol action, Lieutenant Chris Fox received the Military Cross, while Subteniente Llambías-Pravaz was able to pilfer and sport a Commando Beret that the Royal Marines had left behind during the Argentine counter ambush led by platoon sergeant Valdez.

[30]At about 2.10 am local time on 10 June a strong 45 Commando night-fighting patrol attempted to raid and destroy with plastic explosives (according to Corporal Marty Wilkin[31]that took part in this raid along with other men from Recce Troop as pathfinders, who says attached Marine Sappers from Condor Troop were assigned to carry out the demolitions while the rest of the British force pinned down the defenders) the heavy weapons and defensive emplacements of the 3rd Rifle Platoon position.

[32] The British military historian Bruce Quarrie later wrote about the action confirming casualties on both sides: A constant series of patrols were undertaken at night to scout out and harass the enemy.

Heavily armed, with two machine-guns per section, plus 66 mm rocket launchers and 2-inch mortars, the Troop moved off stealthily into the moonlit night towards a ridge some four km away from where Argentine movement had been observed.

However, a machine-gun to the Marines' right was pouring fire over their getaway route, and Stewart sent his veteran Sergeant, Jolly, with a couple of other men to take it out [They knew they were cut off with what looked a poor chance of escape.

Leapfrogging by sections, the Troop retreated to the stream, by which time the Argentine fire was falling short and there were no further casualties.Major Aldo Rico, commander of the 602 Commando Company, had a lucky escape in this engagement, when an enemy 66mm projectile exploded uncomfortably close to him and First Lieutenant Horacio Fernando Lauría.

[33] Captain Hugo Ranieri, who took part in this intense engagement as a specialist sniper, claims that First Lieutenant Jorge Manuel Vizoso-Posse, although wounded, shot three of the retreating Royal Marines in the back.

[37]Then second lieutenant Andy Shaw from Yankee Company disputes this version saying he was in command of the 32-strong platoon that opened fire on a 26-man mortar detachment on the west side of Murrell River.

[52]Naval gunfire rippled back and forth across the mountain, but the Argentine 3rd Platoon of Llambías-Pravaz, shouting their Guarani Indian war cry,[53] held the Royal Marines off and were not dislodged until about 2:30 am local time.

The Argentine mortar platoon commander, Lieutenant Martella, after having consumed all of his ammunition in an earlier attempt to stop the advance of 42 CDO on Mount Harriet was killed in this action.

"[60] The Z Company platoon commander, Lieutenant Clive Dytor, won the Military Cross by rallying his 8 Troop and leading it forward at bayonet point to take 'Summer Days'.

[67][68] Augusto Esteban La Madrid, a second lieutenant in the local reserve tasked with assisting Major Cordon, told British historian Martin Middlebrook that, during the final clashes, "Subteniente Franco's platoon was left as a rearguard, but he made it back to Tumbledown OK".

Sub-Lieutenants Mosquera-Gutierrez and Pérez-Grandi had been wounded in the British bombardment, and the remnants of their platoons were put under the command of Captain Carlos López-Patterson, the Operations Officer of the 4th Regiment, who took up blocking positions in the ground between Mount Tumbledown and Wireless Ridge alongside the dismounted 10th Armoured Cavalry Reconnaissance Squadron under Captain Rodrigo Alejandro Soloaga, engaging at times with heavy machine gun and mortar fire Number 3 Platoon (under Lieutenant David Wright) from A Company 3 PARA on the eastern summit of Mount Longdon and forcing them to relinquish their forward positions and seek cover on the western summit.

Captain Gardiner's X-Ray Company reported another wounded Marine (Corporal Frank Melia) in the daylight hours of 12 June after attracting mortar rounds from Tumbledown Mountain.

[80] On the night of the battle Glamorgan was asked to remain in action longer than planned, to help Yankee Company clear Subteniente Aldo Franco's rifle platoon on the eastern half of Two Sisters covering the Argentine withdrawal.

[85] At 0336 local time, the British skipper, Commander Ian Inskip, looking at the radar screen, realized that Glamorgan was under attack by an anti-ship missile, and ordered a highspeed turn just before the Exocet struck the port side adjacent to the hangar.

Their small individual Lineman entrenching tools were all broken by this time after having constructed solid positions on Mount Challenger and Wall Mountain during May as the Argentinian Regimental Commander explained to British military historian Martin Middlebrook.

[90] Thirty years later, Marine Keith Brown recalled the fighting for the northern peak and concluded My impression of a night attack was that it was nothing like I expected it to be – in terms of a fairly ordered affair with people running and taking out machine-gun nests.

[91]British-American historian Hugh Bicheno has been critical of the 6th Infantry Regiment's 'B' Company who, he claims, withdrew in a disorderly manner from front-line positions at the opening of the battle, although this seems to have little foundation.

Brigadier-General Oscar Luis Jofre had certainly been planning to counterattack on Two Sisters but with the defenders no longer in possession of the twin peaks, he ordered the abandonment of the feature and later wrote All of a sudden, we suffer the first emotional impact.

[95] Sergeant-Major George Meachin of Yankee Company later praised the fighting abilities and spirit of the Argentine defenders of the northern peak in the form of the men of Pérez-Grandi and Mosquera-Gutierrez: We came under lots of effective fire from 0.50 calibre machine guns ...At the same time, mortars were coming down all over us, but the main threat was from those machine-gunners who could see us in the open because of the moonlight.

The still-churned area occupied by Nazer's platoon in particular leaves one in no doubt why they decamped immediately, while the saddle itself is dimpled with craters, testimony to the tenacity of Martella's Heavy machine guns and mortars.With the telephone lines to the command post in shreds, Llambías-Pravaz led his men to join M Company, 5th Marine Infantry Battalion on Mount William and then Sapper Hill.

On the Argentine side, First Lieutenant Jorge Manuel Vizoso-Posse from 602 Commando Company was awarded the Cross for Heroic Valour in Combat for the action that took place on the night of 9/10 June on the western banks of the central part of the Murrell River..[106] 51°41′12″S 58°1′25″W / 51.68667°S 58.02361°W / -51.68667; -58.02361 (Battle of Two Sisters)