Judge Rana Nisar Ahmed of the Rawalpindi-based court, who is conducting the trial of seven Pakistani suspects charged with involvement in the Mumbai attacks, gave his decision after hearing arguments by prosecution and defence lawyers, sources told PTI.
The judge subsequently scheduled the next hearing of the case for April 9.
During the hearing conducted behind closed doors at Adiala Jail in Rawalpindi, the judge questioned the prosecution's plea to declare Kasab and Ansari as "proclaimed offenders" or fugitives and pointed out that they were not deliberately avoiding the proceedings in Pakistan, the sources said.
Lawyers defending the suspects also told the judge that Kasab and Ansari had been in the custody of Indian authorities even before a case was registered by Pakistani law enforcement agencies against the seven suspects, including Lashkar-e-Taiba commander Zakiur Rehman Lakhvi.
The prosecution had wanted Kasab and Ansari to be declared fugitives as their presence in the Pakistani court is required to proceed with the trial of the seven suspects.
A similar plea by the prosecution was earlier rejected by another anti-terrorism judge last year.
The defence lawyers have argued that Kasab had already been convicted and sentenced to death by a court in India and he could not be tried again in Pakistan.
They contended that the prosecution wanted to produce witnesses like Kasab and Ansari to whom it had no access and this had resulted in "inordinate and indefinite" delays in the proceedings in the anti-terrorism court.
They also asked the prosecution to present the evidence it had so that the trial against the seven suspects could get underway. The trial of the seven Pakistani suspects has been marred by repeated delays over technical matters.
The judge has been changed thrice and only one of more than 160 prosecution witnesses has testified so far.