The Delhi High Court tribunal on Wednesday upheld the central government's decision to extend the ban imposed on the Students Islamic Movement of India (SIMI).
In February this year, the home ministry extended the ban by another two years on the SIMI after which the matter reached the tribunal for review.
The tribunal's order upholding the ban was sent to the ministry in a sealed cover.
Mobin Akhtar, counsel appearing on behalf of SIMI, said they will examine the case and contest it in the Supreme Court.
He said the evidence produced by the government was based on the confessional statements of people arrested in the 2008 Delhi serial blasts.
"Merely on the basis of confessional statements one cannot extend the ban on an organisation. The government (is trying) to show that the SIMI is linked to terrorist activities when they have nothing concrete to produce as evidence," said Akhtar.
By a notification Feb 7, 2008, the home ministry extended the ban on SIMI for two years.
The ministry said SIMI has close links with several international and national terror outfits, the Al Qaeda and underworld don Dawood Ibrahim.
On Aug 5, 2008, High Court Judge Geeta Mittal lifted the ban on SIMI.
The tribunal court pronounced the judgment on the grounds that the evidence against SIMI was not enough to justify the extension of ban under the Unlawful Activities (Prevention) Act.
A day after the tribunal's judgment, the Supreme Court stayed the order of lifting the ban.
Later, the ministry filed a fresh affidavit in the apex court that claimed that around 1,900 SIMI activists were presently in prisons across the country, with 89 cases registered against them.