Nnamdi Kanu, fugitive leader of the outlawed Independent People of Biafra (IPOB), visited some countries before INTERPOL nabbed him.
Kanu, who was flown into Nigeria on Sunday, appeared before Justice Binta Nyako of the Federal High Court in Abuja on Tuesday.
The judge ordered that he should be remanded in custody of the Department of State Services (DSS) till July 26.
Abubakar Malami, Attorney-General of the Federation, who announced the arrest of Kanu at a media briefing on Tuesday, did not state where he was nabbed.
But Daily Trust gathered that the IPOB leader visited Singapore and went to the Czech Republic on Friday en route to the UK.
But he was arrested on Saturday in Prague, The Czech Republic, and flown back to Nigeria on Sunday.
A source said Kanu might have been nabbed following a tip-off from a European country to the INTERPOL.