NEW YORK — Mayor Zohran Mamdani drew criticism from both Democrats and Republicans on Wednesday after posting a statement for the third anniversary of Hamas’ Oct. 7, 2023, attack on Israel that devoted much of its attention to Israel’s war in Gaza. Mamdani called the Hamas attack a “horrific war crime.” He then argued that Palestinian suffering preceded the attack and has continued during Israel’s military campaign, which he characterized as genocide. “The suffering did not begin nor end that day,” Mamdani wrote. He cited figures of more than 74,000 Palestinians killed in Gaza, including more than 21,000 children. Those figures were presented in his statement; they were not independently established in the information available for this report. The timing intensified the response. Critics said the anniversary was an occasion for elected officials to focus on the victims of the Hamas attack rather than issue a message centered largely on Israel’s conduct. The statement drew millions of social-media views, and even some Democrats were taken aback, according to accounts of the reaction. Mamdani has long been a critic of Israel and has repeatedly condemned its treatment of Palestinians since the October 2023 attack. His statement underscored the political challenge facing officials addressing the conflict: acknowledging the attacks and their victims while speaking about the vast Palestinian toll and the consequences of Israel’s military response.