In all, something like 3,000 Babis died in these episodes...

In all, something like 3,000 Babis died in these episodes, or, if we take the lower figure of 1,000 deaths at Zanjān, just over 2,000 in all. Later estimates of 20,000 and more found in some Bahai works do not, in fact, correspond to the more detailed figures given in Bahai historical sources. Similarly, the very high figures for both participants and casualties given in state chronicles like the Nāseḵ al-tawārīḵ are manifestly exaggerated, probably in order to explain away the failure of the government forces to put down the disturbances rapidly.

http://www.iranicaonline.org/articles/babism-index

Also check : https://bahai-library.com/uhj_mazandarani_number_martyrs