Yahya Sinwar was re-elected Wednesday as the head of Hamas's political wing in Gaza, extending his tenure as the Islamist movement's de facto leader in the Israeli-blockaded Palestinian enclave, Hamas said.  

Sinwar, a former commander of Hamas's military branch, served more than two decades in an Israeli prison before he was released in 2011 as a part of a prisoner exchange. 

First elected to the post in 2017, he faced four challengers this time, including Nizar Awadallah, the former head of Hamas's advisory Shura Council.

Hamas's overall chief Ismail Haniyeh, currently based in Qatar, congratulated Sinwar in a statement. 

"The movement's commitment to (internal) elections every four years confirms our deep faith in the principle of rotating power," Haniyeh said. 

Sinwar's re-election comes ahead of May 22 Palestinian legislative polls, the first Palestinian vote in 15 years.

Hamas, which has controlled the Israeli-blockaded Gaza Strip since 2007, is a key player in that vote, along with the Fatah movement led by Palestinian president Mahmud Abbas. Fatah controls the Israeli-occupied West Bank.

Haniyeh said the success of Hamas's internal election reinforced its "seriousness" ahead of the legislative poll and a Palestinian presidential election set for July 31. 

Elections for Haniyeh's post are also expected soon. He is due to run against his deputy Jamal al-Aruri and former Hamas chief Khaled Meshal. 

In addition to its political wing, Hamas has an armed branch that counts thousands of fighters in Gaza.

The Islamist group is considered a terrorist organisation by much of the Western world.