"....one day or the other, (the) US will have to agree and expedite the issue that Headley will have to undergo interrogation by our agencies", Union Law Minister M Veerappa Moily said.
On whether US denial to give India a direct access to Headley was 'unfair' and 'unjustified' on the grounds that Indian government had allowed the FBI to interrogate gunman Ajmal Kasab in Mumbai, Moily said it would be unfair to pass judgement on their legal systems.
"We don't want to pass a value judgement on their policy and matter," he said.
However, Moily said that India will continue to press hard until United States agrees to its demand.
"But this is a matter we need to hard press our argument and you know we have a strong bargaining and tell them (the US) what's necessary...we have to make a strong case which we have already made out. Here (Mumbai attacks) he (Headley) is involved, he is really involved".
Earlier on Tuesday, Mar 23, US Ambassador Timothy J Roemer said that US is yet to arrive on any decision on India's direct access to David Headley, just four days after he publicly said in Delhi that Indian investigators would have an access to Headley.