The blast struck the right side of the first vehicle in a seven vehicle convoy on a reconnaissance patrol some 20 kilometres (12 miles) north of Qala i Naw in the northwestern province of Badghi, she told a Madrid news conference.
"The preliminary investigation indicates that the amount of explosives used by the insurgents was very high," the minister said before heading to Afghanistan to accompany the remains of the soldiers back to Spain.
The two soldiers, a man and a woman, died instantly in the blast while the three injured troops were taken by helicopter to a hospital in the village of Bala Murghab with broken bones. Their lives are not in danger.
The deaths come just eight days after four Spanish soldiers and their civilian interpreter were injured when their armoured vehicle hit an explosive device in Badghi province. Two soldiers had to have a leg amputated.
The device that caused that blast contained over 20 kilos of explosives. Chacon said the one which went off on Sunday likely employed a "similar or even greater amount" of explosives.
"This is the second attack which our troops in Afghanistan have suffered in eight days. Unfortunately this demonstrates that this is the most difficult, most complex and most risky mission which our armed forces have become involved in in the last decades," the minister added.
There are around 130,000 NATO-led international troops fighting the near decade-long Taliban insurgency.
A limited withdrawal of foreign troops is expected to begin in July, ahead of a planned transition of responsibility to Afghan security forces due to be completed by end of 2014.
Spain will pull out 10 percent of its forces by the end of the first half of next year, Spanish Prime Minister Jose Luis Rodriguez Zapatero said Friday at a European Union summit in Brussels.
By the end of the first half of 2013 another 40 percent will be withdrawn and a full pull-out will take place in 2014, he added.
The Spanish troops are training Afghan army personnel to maintain peace, security and stability. (*)
Editor: Kunto Wibisono
Copyright © ANTARA 2011
