Fighting between Israel and Hamas reached the 10-month mark on Wednesday. Health officials in the Gaza Strip say the death toll is approaching 40,000.

Concerns are growing that tensions in the Middle East could lead to a wider conflict.

A huge billboard depicting Hamas political leader Ismail Haniyeh clasping hands with Iranian President Masoud Pezeshkian has been erected in a square in Tehran. Haniyeh was assassinated last week, and Iran blames Israel for his killing.

Tehran is trying to build support for an anticipated retaliation, and that's prompting unease.

A resident of the Iranian capital said: "We must consider how Israel would react if we strike back. This country would be crippled if even one power plant was attacked."

Iran is also seeking outside support.

The Organisation of Islamic Cooperation held a foreign ministers meeting on Wednesday at Iran's request.

Hamas announced the day before that it had chosen its top official in Gaza, Yahya Sinwar, as the group's new political leader.

Analysts say that may stall ceasefire talks.

Sinwar is one of Israel's top targets as it tries to eliminate Hamas.

The country's military accuses him of masterminding the deadly October 7 attack on Israel that sparked the conflict.

Israel Defense Forces Spokesperson Daniel Hagari said there is only one place for Yahya Sinwar, and that is next to all the terrorists who carried out the attack.

Nasser Hospital is a key facility in the south end of the Gaza Strip.

Japanese nurse Motokawa Sakiko works there as part of the international nongovernmental organization Doctors Without Borders.

Motokawa said: "Most of the patients have been taken to this hospital with injuries or burns from the airstrikes. If we accept too many patients at one time, we have to discharge them from here even if they are not fully recovered or in a stable condition."

Children account for many of the dead in the enclave. Acute malnutrition is a common ailment among young people there.

Motokawa said: "I believe citizens are hoping for a ceasefire. I hope no more citizens will be hurt."

But there is no sign of an end to the fighting. Local news outlets report Israeli military attacks killed three people on Wednesday.