Antony said that based on an on-the-spot assessment by Army Chief General Bikram Singh, it is now clear that the attack was carried out by Pakistani army regulars.
The defence minister was making a fresh statement in parliament on Tuesday's incident in which five Indian army soldiers were killed on the LoC in Jammu and Kashmir by intruders from the Pakistani side of the Line of Control which divides Jammu and Kashmir between India and Pakistan.
"The chief of army staff visited the area and it is now clear that specialist troops of Pakistan Army were involved in this attack when a group from Pakistan Occupied Kashmir (PoK) crossed the Line of Control (LoC) and killed our brave jawans," Antony said in a statement.
"We all know that nothing happens from Pakistan side of the LoC without the support, assistance, facilitation and often direct involvement of the Pakistan Army," added Antony.
He called upon Pakistan to punish those responsible for this attack and the one early this year when one soldier was beheaded and the body of the other was mutilated.
"Those in Pakistan who are responsible for this tragedy, (and) brutal killing of our two soldiers earlier this year should not go unpunished," he said.
"Pakistan should also show determined action to dismantle the terrorist networks, organisations and infrastructure and do tangible movement on bringing those responsible for Mumbai terrorist attack in November 2008 to justice quickly," he said.
He said the incident will impact relations between the two countries.
"Naturally this incident will have consequences on our behaviour on the LoC and for our relations with Pakistan. Our restraint should not be taken for granted nor should the capacity of armed forces and resolve of the government to uphold the sanctity of the LoC ever be doubted," he added.
The defence minister was making a fresh statement in parliament on Tuesday's incident in which five Indian army soldiers were killed on the LoC in Jammu and Kashmir by intruders from the Pakistani side.
Antony was under attack from the opposition for his earlier statement where he had told parliament that "20 heavily armed terrorists along with persons in Pakistan Army uniform" were responsible for the killings.
An earlier defence ministry statement - which was withdrawn later - stated that the ambush was carried out by a Pakistani Border Action Team.
It also said that the Pakistan Army was involved in the attack. Pakistani Border Action Teams comprise Pakistani Army regulars and militants.