JERUSALEM (AFP) - Israeli Prime Minister Benjamin Netanyahu said Sunday there was "very strong" international support for the military's ongoing operation in Gaza that has killed more than 430 Palestinians in 13 days.

"We are carrying out a complex, deep, intensive activity inside the Gaza Strip and there is world support for this ... very strong support within the international community for the activity that the IDF is doing," he said at a press conference in the defence ministry in Tel Aviv.

Netanyahu has said Israel won "international legitimacy" for its military operation in Gaza after it accepted an Egyptian truce proposal on July 15 which was shunned by Hamas.

His remarks came shortly after US Secretary of State John Kerry blamed Hamas for perpetuating the bloody conflict in Gaza by "stubbornly" refusing all ceasefire efforts.

By its behaviour, Hamas had "invited further actions" by Israel, he said. "War is ugly, and bad things are going to happen. But they need to recognise their own responsibility," he said.

Netanyahu said the operation in Gaza would "expand as much as necessary" to restore the quiet for Israeli citizens.