Israeli troops arrested the Hamas representative on the organising committee for October Palestinian municipal elections on Wednesday, the Islamist movement said.
Hamas condemned what it called an "attempt to influence" the outcome of the elections, the first in the Palestinian territories since 2012.
"We condemn the arrest of Sheikh Hussein Abu Kweik," a Hamas statement said, adding that he had been detained in the early morning in the occupied West Bank.
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Elections committee spokesman Fareed Tamallah condemned the "blatant interference in Palestinian local elections by (Israeli) occupation forces," and demanded Abu Kweik's immediate release.
The October 8 vote will be only the third Palestinian municipal elections since Israel and the Palestinians signed the Oslo peace accords in 1993.
Hamas has agreed to field candidates this time after boycotting the last elections in 2012. Registration began on Tuesday.
There have been no Palestinian parliamentary elections since 2006 when Hamas won by a landslide.
The following year conflict broke out between Hamas and the rival Fatah faction of Palestinian President Mahmud Abbas, leading to the ouster of his loyalists from Gaza and the formation of rival administrations.
Repeated attempts at forming a unity government to rule both Gaza and the West Bank have all failed.