An SAS soldier manufactured an account of the shooting of two IRA members to cover up the use of excessive force, it was claimed at an inquest on Friday.
Dessie Grew, 37, and Martin McCaughey, 23, died when troops fired 72 bullets at the pair near farm buildings in Co Armagh in October 1990.
The military witness, who gave evidence from behind a curtain at Laganside courts in Belfast, was identified only as Soldier C.
A barrister representing the men's families, Karen Quinlivan, contested claims he fired 19 rounds because he believed he was under attack, though it later emerged the republicans did not shoot.
Quinlivan said: "That is an account that you have made up in order to justify the excessive force that you used on the night in question."
Soldier C confirmed the troops had the mushroom shed near Loughgall under surveillance amid suspicions a stolen vehicle inside was to be used for terrorism.
He confirmed troops gave no warning before firing, but he rejected claims he had fabricated his account and said he had opened fire in response to flashes that later emerged to have been caused by bullets fired by the soldiers.
The jury heard Soldier C had claimed to have opened fire because he believed his life and those of the other troops were at risk.
After a colleague started shooting at the two men, Soldier C said: "I thought there were more men.
"More men could be hiding. I seen flashes that I thought were muzzle flashes."
The inquest, which is in its fifth day, has already heard from a doctor who examined the dead men and said they were lying near guns.
The inquest is one of several so-called security force "shoot-to-kill" incidents which have sparked controversy and a series of official investigations.
The officer commanding at the time of the present matter, Soldier K, has denied there was a policy of shoot to kill.
Soldier C said he did not have a view of the two men and could not see if they were armed, though a warning to that effect came from a colleague.
He said he saw flashes through his night vision gun sight and moved forward with another soldier, firing as they closed in on the barn.
"It is a lot safer for us to do that than sit there and do nothing," he said.
He later said the circumstances were tense: "It was a very serious situation I put myself in."
The barrister for the families said: "You are going to keep shooting until those men are dead, isn't that right Soldier C?"
He answered: "That is not correct."
The soldier said firing stopped when they believed the shots being fired at troops had ended, but the barrister questioned this account because the troops were responding to flashes caused by their own bullets.
Quinlivan challenged his claims that he was unaware on the night that the republicans had not fired and only found this out later, even though at least one other colleague was aware in the immediate aftermath.
She said: "I am suggesting to you Soldier C that what you are saying makes absolutely no sense."
The soldier answered: "That is your opinion and you are welcome to it."
The soldier denied he was part of a planned ambush.
The barrister for the families pointed to changes in statements he had given, but he defended his accounts.
She asked why the guns by the bodies of the wounded republicans were not kicked away from them.
"We still did not know how many other individuals were in the barn," he said.
The lawyer asked: "If the intention was not to finish people off...you would have got the guns off them for your own safety."
She added: "Do you just make this up as you go along Soldier C?"
Quinlivan put it to the soldier that he had seen Soldier D fire fatal shots into the two republicans as they lay wounded.
Soldier C denied this and denied troops had compiled accounts to cover-up events.
In reply to questions from the barrister for the Ministry of Defence, David Perry, the soldier said the shootings were over in 15 to 20 seconds.
He said the flash of gunfire had glared his night vision equipment.
"At the time there is a cacophony of sound inside the yard," said the soldier.
"When we are firing a high velocity rifle the discharge from the weapon is extremely loud.
"Your blood is pumping."
He added: "I believed my life and the lives of my team members were in danger."
The inquest continues.