Muslim-majority Malaysia is a supporter of the Palestinian cause and Anwar had posted a video recording of his phone call with a Hamas official to offer condolences over Haniyeh’s death, which was later removed.
Haniyeh’s assassination in Iran on Wednesday has added fuel to concern the conflict in Gaza was turning into a wider Middle East war.
Anwar, who met Haniyeh in Qatar in May, has said he has good relations with the Hamas political leadership but no links on a military level.
“Let this serve as a clear and unequivocal message to Meta: Cease this display of cowardice,” Anwar posted on his Facebook page.
Meta did not immediately respond to a request for comment on Thursday.
Malaysia’s Communications Minister Fahmi Fadzil said an explanation had been sought from Meta and it was unclear whether the posts were automatically removed, or taken down following a complaint.
Meta has designated Hamas, the Palestinian Islamist movement that governs Gaza, as a “dangerous organisation” and bans content praising the group. It also uses a mix of automated detection and human review to remove or label graphic visuals.
Malaysia has previously complained to Meta over its takedown of content, including local media coverage of Anwar’s last meeting with Haniyeh, which was later restored.
Meta at the time said it was not deliberately suppressing voices on its Facebook platform and was not restricting content supporting the Palestinians.
Malaysia has long advocated a two-state solution for the conflict between Israel and the Palestinians