Police have cordoned off BNP chief Khaleda Zia's Gulshan office a day before the party plans agitations to mark the first anniversary of the last general elections.

The law keepers have also searched and locked the party's central office at Naya Paltan.

"Khaleda Zia has been besieged by the law-enforcing agencies since 11:40pm," her special aide Shamsur Rahman Shimul Biswas told reporters around 1am on Sunday.

Earlier, detective police picked up BNP's Joint Secretary General Ruhul Kabir Rizvi from the party's headquarters.