Israel’s prime minister, Benjamin Netanyahu, has said he will take on the defence minister portfolio, rejecting calls to dissolve his government even as early elections appeared increasingly likely.

Netanyahu said heading to elections now, amid repeated violent confrontations with Gaza militants, was “irresponsible” of his coalition partners, who have been pushing for early polls since the resignation last week of the defence minister, Avigdor Lieberman, over a Gaza ceasefire.

“Today, I take on for the first time the position of defence minister,” said Netanyahu on Sunday, speaking from Israel’s defence headquarters in Tel Aviv in a statement broadcast live at the start of the evening news. “We are in one of the most complex security situations and during a period like this, you don’t topple a government. During a period like this, you don’t go to elections.”