Amid a chill in Indo-Pak ties, US Assistant Secretary of State Richard Boucher arrives in New Delhi [Images] on Thursday from Pakistan to discuss the situation arising out of the Mumbai terror attacks [Images].

Also Read: Attacks on Mumbai

Boucher will meet Foreign Secretary Shivshankar Menon and the two sides will deliberate on how Pakistan-based perpetrators of the Mumbai strikes can be brought to justice.

The two sides are expected to discuss how Pakistan could be made to cooperate in pursuing the leads into the terror attacks that go into that country.

Boucher has bluntly told Pakistani authorities that Mumbai attackers had links in Pakistani soil and Islamabad [Images] should pursue these and track down the perpetrators of the terror strikes.

India has already given to Pakistan a dossier of evidence about involvement of LeT whose 10 heavily-armed terrorists came from Karachi to launch attacks in Mumbai on November 26.

The dossier includes confession of Ajmal Amir Kasab [Images], the lone terrorist arrested during the Mumbai attacks, and material and technical evidence.

Boucher has said the US has a 'direct interest' in the probe as six of its citizens were killed in the Mumbai attacks.

"We are interested that those responsible must be found."

The Federal Bureau of Investigation of the US also has conducted a separate probe into the attacks. The FBI has questioned Kasab and also has other technical evidence regarding involvement of Pakistan-based terrorists in the attacks.