Air strikes on the Gaza Strip killed a top Hamas weapons maker and several fighters, the Israeli military has said.

Gaza City, Hamas main stronghold on the coastal enclave, is encircled by Israeli forces. The military said troops have advanced to the heart of the densely-populated city while Hamas says its fighters have inflicted heavy losses.

The Israeli military statement said two separate strikes eliminated a leading Hamas armourer, Mahsein Abu Zina, and fighters engaged in anti-tank or ground-to-ground rocket fire.

Palestinian media also reported clashes between militants and Israeli forces near al-Shati (Beach) refugee camp in Gaza City.

Reuters was unable to verify the battlefield claims of either side.