Yaffa Ben-David, Secretary-general of the Israel Teachers Union, showed a photo on Wednesday of hostage Ohad Yahalomi during a United Nations Security Council meeting and was subsequently escorted out.
A meeting of the Security Council on the Middle East was briefly interrupted on Wednesday when she and another protester stood with signs and yelled for the release of Israeli hostages held by the Hamas terrorist organization in the Gaza Strip.
The demonstration by two women came as Russian Foreign Minister Sergei Lavrov began to address the 15-member body after a statement by Israel's UN Ambassador Gilad Erdan. Protests inside the UN headquarters in New York are rare.
Lavrov: "I don't understand, speak clearly"
Lavrov, who was chairing the meeting because Russia is the council president for July, responded: "I don't understand, speak more clearly. One of you can speak clearly to say what you want to say. I see you don't wish to do so, very well."
Diplomats in the Security Council chamber said the women, dressed in black, yelled "free the hostages." UN security asked the women to leave the chamber and they did so, a UN official said.
Israel's UN mission did not immediately respond to a request for comment on the protest.
The war in Gaza - a Palestinian enclave of 2.3 million people - began when Hamas attacked southern Israel on October 7, killed 1,200 people and took around 250 hostages, including civilians and soldiers, back into Gaza.
Israel then launched a ground and air assault that has killed nearly 39,000 Palestinians, the Hamas-run health ministry's authorities say.
Reuters contributed to this report.