New Delhi, March 21 (IANS) External Affairs Minister S.M. Krishna says that Indian aid workers in Kabul have become "soft targets" for terrorists who want to derail India-Afghan relations.

"I think (the Feb 26 Kabul attack that killed seven Indians) has been the handiwork of those forces who are out to see that the relationship between India and Afghanistan is jeopardized," Krishna told a TV channel.

Asked if the US had agreed that the attack Pakistan-based Lashkar-e-Taiba outfit masterminded that attack, the minister told CNN-IBN that America "cannot come to any other conclusion other than to accept that it was the handiwork of these terrorist organizations".

He said the US "certainly" does understand that as it is "a close observer of these developments both in India and in Pakistan and in Afghanistan, because they have so much at stake in Afghanistan".

The minister said there was a warning that Indian missions and volunteers on humanitarian work in the war-torn country "are going to be under attack because what India has been doing in Afghanistan is the visible symbol of what India intends to do in building up Afghanistan.

"The Indians who have gone there to Afghanistan on humanitarian purposes are unarmed. So, naturally they become easy targets, soft targets," Krishna said.

He said Kabul had vowed to protect Indians in Afghanistan.

However, he said, "apart from what the Afghanistan government is doing, I think we will have to take some additional measures ourselves".

He refused to divulge details. "We will have to be on our guard. We will have to realize the tremendous risks involved when we are on a humanitarian mission like the one we have in Afghanistan."