Terrorists, who struck Mumbai had set up an advance control room in the luxury Taj and Trident(Oberoi) hotels and had done prior reconnaisance, a Union Cabinet minister said on Thursday.

The minister who requested anonymity said that the security agencies were piecing together various leads in the probe on India's worst ever terror strike.

• Terror strikes at Mumbai's heart

The minister also said the terrorists cannot execute the operation of the magnitude of Wednesday's attack without making any recee or setting up a control room type mechanism.

Amid reports that a likely marine arm of the Pakistan-based Lashkar-e-Toiba may have been involved in the well-planned attacks that left over 100 persons dead, the Union home ministry said the terrorists chose the sea route and came to the city in boats before spreading out in the metropolis to carry out the sinister action.

The assessment by the Centre as Mumbai continued to be under siege for the second day came amid reports that that the leader of the armed terrorists involved in the attack was killed by his own men.

Vice-Admiral J S Bedi, Flag Officer Commanding, Western Naval Command said his elite Marcos naval commandoes who confronted the terrorists in the Taj Hotel seized stun grenades, hand grenades and other sophisticated ammunitions and ATM cards besides US dollars from the terrorists.

The terrorists were also found to be carrying huge loads of almonds, which can be used as food during a long siege.

"They (the terrorists) came by the sea route," special secretary (internal security) in the Home Ministry M L Kumawat said while replying to questions at a press conference in Mumbai.

Kumawat said the terrorists, claiming themselves to be from a hitherto unknown Deccan Mujahideen [Images] outfit, took the coastal route and landed at Sasoon Dock. From there they changed over to boats to reach the shore, he said.

Asked about the identity or nationality of the terrorists, Kumawat declined to reveal any detail saying it would hamper the investigations. Roy also declined to speculate on this issue.

A Mumbai report quoting authoritative sources pointed to the involvement of at least some Pakistani nationals in the serial terror attacks.

"There are indications that the perpetrators of the crime, who arrived in Mumbai by boats, are Pakistani nationals," they told PTI on the basis of information gathered from captured terrorists.

Maharashtra Deputy Chief Minister R R Patil, who also holds the Home portfolio, said: "we have total clues. But disclosing information would not help the case".

The Colaba police have impounded four boats allegedly used by the terrorists to reach the Mumbai coast.