Chennai, Jan 8 External Affairs Minister Pranab Mukherjee Thursday said the constant "flip-flop" by Islamabad in admitting that the Nov 26 Mumbai terror attack was plotted on Pakistani soil was unfortunate and recalcitrant.

"Our job has been vastly facilitated by virtue of the fact that we have one of the terrorists in physical custody," Mukherjee said at the seventh Pravasi Bharatiya Divas here, referring to the captured terrorist Ajmal Kasab.

"He has told us categorically where he comes from, where he has received military and arms training, where his handlers are located," the Indian minister said.

"Unfortunately, despite this, we have seen a consistent flip-flop in the reaction of the government in Islamabad."

He thanked the international community for expressing both anger at the "external hand" involved in the Mumbai terror attack and sorrow for the number of people who died during the three days of carnage.

"We are deeply grateful for the sympathy that poured out of all quarters, including at the level of common people. At the same time, after over a month of the operation, there continues to be recalcitrance in bringing the perpetrators to justice."

The minister exhorted members of the Indian diaspora to do much more to ensure that the country and the world at large wins the battle against terrorism.

"As our ambassadors abroad, your words will be heard in multiple corners of the globe. I call upon all of you to join us in playing the important role of taking forward our concerns to the world stage because these are concerns you also share," he said.

He said while India was capable of handling multiple challenges, the country could succeed in her journey only if "sponsored terrorism" was resoundingly defeated - financially, monetarily, militarily and politically.

"I believe this to be the singularly unique terrorist strike since 9/11 and hence I believe that it is important that anti-terrorist wings in all countries take cognisance of this operation and bring the perpetrators to justice," he said.

"Let us not forget that terrorism knows no borders - all of us are vulnerable."