Apna Dal leader Anupriya Patel was placed under preventive arrest in Bareilly, and Indian Justice Party national president Udit Raj was also detained.
Officials said the leaders were detained due to tension in Allahabad over the pro-reservation rally.
"The situation is tense and political leaders are not being allowed as anti-reservation activists have also declared a retaliatory march," an official told IANS.
The Allahabad district administration has banned any rally or public gathering in the city and prohibitory orders under Section 144 have been clamped.
Sharad Yadav, who was taken off the Duranto Express train taking him to Allahabad, said Uttar Pradesh Chief Minister Akhilesh Yadav has "lost touch with ground realities".
Sharad Yadav was kept in a guest house in Ghaziabad and later sent back to Delhi by the state police.
The issue of reservation has been simmering for some time now over the issue of a three-tier reservation policy in public services examinations.
--IANS (Posted on 17-09-2013)