ED added that the accused persons were "withholding the information relevant for investigation".
The Enforcement Directorate on Thursday alleged in a Delhi court that former Union minister P Chidambaram and his son Karti "withheld information" from it and the Central Bureau of Information about certain foreign bank accounts during the probe in Aircel-Maxis cases.
Solicitor General Tushar Mehta and senior advocate Sonia Mathur, appearing for the ED, told the court that the probe agency has also come across the fact that Advantage Strategic Consulting Pte Ltd, Singapore, was "beneficially owned" by the Chidambarams and received funds from a company whose name allegedly figured in the Panama Papers.
The company, from which Advantage Strategic Consulting Pte Ltd, Singapore received funds, is registered in British Virgin Island, the law officer alleged.
Taking into account the submissions of the agency, Special Judge O P Saini granted time till August 1 to ED to complete probe into the foreign bank accounts.
The court then took note of the submissions of senior advocates Kapil Sibal and Abhishek Manu Singhvi, appearing for the father-son duo, and extended their interim protection against arrest.
The top Congress leaders and senior lawyers initially opposed the ED's plea for an adjournment alleging that the agency has been repeatedly seeking deferment of the proceedings.
During the hearing, Tushar Mehta said, "None of the applicants had divulged about the foreign account of M/s Asdvantage Strategic Ltd., Singapore in spite of the fact that both of them are holding the same company either directly or indirectly. It was the investigating agency that found out the bank account."
The law officer further said that there were eight foreign bank accounts which were not divulged to the investigating agencies, ED and the CBI.
"Crucial details pertaining to source of deposits and reasons for withdrawal from these bank accounts are still awaited from Singapore authorities," he said.
The agency submitted that the issue was "promptly attended to by the ED by sending a team of officers led by the Special Director of ED to Singapore and it is expected that the said details, which will be crucial for adjudication of anticipatory bail as well as taking cognizance (of the charge sheet), would be received soon."
The transactions routed through these bank accounts are crucial, both for completing the investigation and assisting this to satisfy as to why custodial interrogation of the accused is required, it said.
A team of lawyers including advocates N K Matta, Nitesh Rana, A R Aditya and Noor Rampal appeared for ED in the case.
ED added that the accused persons were "withholding the information relevant for investigation".
"It clearly appears that the real intention for pressing (by accused) for earlier hearing of this case and praying for anticipatory bail and taking cognisance is to ensure that this court is deprived of the details of foreign bank accounts which is shortly expected.
"The probe agency has also come across that M/s Advantage Strategic Consulting Pte. Ltd., Singapore, beneficially owned by the accused, has received funds from a company figured in Panama papers and registered in British Virgin Island," the agency said.
The case relates to alleged irregularities in grant of Foreign Investment Promotion Board (FIPB) approval in the Aircel-Maxis deal.
The duo approached the court seeking anticipatory bail, claiming that they were afraid of arrest in both the cases being probed by the ED and the CBI.
Their protection from arrest has been extended from time to time.
Mr Chidambaram and his son Karti were named in the charge sheet filed by the CBI in the case on July 19 last year.
The CBI is probing how Mr Chidambaram, when finance minister in 2006, granted FIPB approval to a foreign firm, when only the Cabinet Committee on Economic Affairs (CCEA) was empowered to do it.
The CBI and the ED, in their replies to the anticipatory bail pleas, had told the court that custodial interrogation of both the accused was required since various new materials have surfaced after filing of the charge sheet, alleging that they were not cooperating in the probe.
They have come under the scanner of investigating agencies in the Rs 3,500-crore Aircel-Maxis deal and the INX Media case involving Rs 305 crore.
In the charge sheet filed earlier in the case against former telecom minister Dayanidhi Maran, his brother Kalanithi Maran and others, the CBI alleged that Chidambaram granted FIPB approval in March 2006 to Mauritius-based Global Communication Services Holdings Ltd, a subsidiary of Maxis.
The Maran brothers and the other accused named in the CBI charge sheet were discharged by the special court, which said the agency had failed to produce any material against them to proceed with the trial.
The ED is also probing a separate money laundering case in the Aircel-Maxis matter, in which the Chidambarams have been questioned by the agency and their anticipatory bail is pending.