Bangladesh police have arrested more than 10,500 opposition activists ahead of elections this week, AFP reported quoting statements by opposition parties.

Opposition parties said the arrests since the election was called on November 8 were intended to create a "climate of fear".

The main opposition Bangladesh Nationalist Party (BNP), whose leader Khaleda Zia is serving a 17-year jail term, said 7,021 of its activists had been detained.

Its Islamist ally, Jamaat-e-Islami, said more than 3,500 followers were in custody. Jamaat-e-Islami is banned from contesting elections but has candidates taking part as individuals with the BNP.

"Every day 80 to 90 of our activists have been arrested nationwide. These arrests have created a climate of fear," Jamaat secretary general Shafiqur Rahman told AFP.

Police spokesman Sohel Rana did not confirm any figure for arrests, but said they did not make "unnecessary arrests" without warrants.