By Nidal al-Mughrabi and Bassam Masoud CAIRO/GAZA (Reuters) – Israeli troops and Hamas militants fought fierce gunbattles on the streets of Gaza’s second-biggest city on Wednesday as the United Nations delayed a vote on a bid to boost aid deliveries to the Palestinian enclave facing a humanitarian disaster. Israel’s campaign to eradicate Hamas militants behind an Oct. 7 massacre has left the coastal enclave in ruins, brought widespread hunger and homelessness, and killed nearly 20,000 Gazans, according to the Palestinian enclave’s health ministry. Under foreign pressure to avoid killing innoce…