Expressing serious concern over the alleged involvement of a serving Army officer in the Malegaon blast, the Centre on Friday said necessary action will taken against him by the defence ministry on the basis of the Maharashtra police's investigation report in the case.

The government said it would go to the root of the September 29 blasts that claimed six lives and in which a lieutenant colonel is suspected to be involved.

"This incident is a matter of serious concern for all of us. We are very determined to go to the root of the whole thing," Antony told reporters here soon after an awards function for defence PSUs.

"We are awaiting the (Maharashtra police) report (in the case). We will take all necessary action on the basis of the report," Antony said, when asked to react on the involvement of a serving Military Intelligence officer in the blast.

Evading a direct reply on the involvement of more serving officers, including one holding a senior rank, Antony said the Army was fully assisting the investigation "without any hesitation" and so was the defence ministry.

"On the part of the Army, without any hesitation, they are fully assisting and cooperating with the investigating agencies. We are waiting for a report from the Maharashtra police and I can tell you, we are taking it seriously," he added.

\Pointing out that the Maharashtra police and the Intelligence Bureau, were investigating the whole issue, Antony said the inquiry by the agencies outside the MOD was going on. "On the part of the MOD and Army, we are assisting them -- the Maharashtra police and IB. And we are also internally taking steps whatever is needed," Antony said.

Asked if he was satisfied with the investigation by the Anti-Terrorism Squad of the Maharashtra police into the Malegaon blast, he said: "I am not here to give judgment (on the probe). We will extend all assistance and cooperation to the Maharashtra police and IB."

The ATS had on November 4 arrested Lt Col Shrikant Prasad Purohit for allegedly masterminding the Malegaon blasts after the Army gave its nod to detain him.

The ATS produced Purohit before a Nashik court, which remanded him to police custody for further questioning in the case.

There are reports that more serving Army officers, including a senior-ranked officer, had prior knowledge of Purohit's plans and had complicity in the blasts.

Though the ATS had claimed that it plans to interrogate some more Army officers in the case, the Army has said it was yet to receive any request from the police for questioning more officers from its ranks.