It is devastating that it took six months and the killing of six western aid workers for a tipping point to be reached for Israel to change course over the supply of international humanitarian aid, the chair of the UK foreign affairs committee has said. Speaking to BBC Radio 4’s Today programme, Alicia Kearns said the government must suspend arms sales to Israel and claimed ministers were no longer saying that Israel was complying with international humanitarian law, merely that it had the capacity to do so. “I believe we have no choice but to suspend arms sales and it is important that the public understands this is not a political decision as some people want to present it as,” she said. “Legal advice is advisory so the government can choose to reject it but UK arms export licences require a recipient to comply with international humanitarian law. That is why emergency handbrakes exist in terms of change of circumstances.” Kearns said it was frustrating that Joe Biden was only now calling for an immediate ceasefire when only a week ago his aides had said a UN security council resolution calling for a ceasefire was non-binding, reducing its impact. She rounded on fellow Conservatives who seek to have a monopoly on how to support Israel, saying support for an extremist Likud-led government was not the same as support for Israel. She said the way Israel was prosecuting its right to self-defence was making it and the world less safe. “So many people have said to me ‘why can’t you force Israel to do this?’. Israel is our ally and we do not control them,” she said. “The phrase we have heard from interlocutor after interlocutor is that Israel is not listening. That does appear to have changed. The priority for now is very much making sure for aid to be getting in and that famine must be stopped.” Referring to a phone call on Thursday between Biden and Benjamin Netanyahu, Kearns said: “It is frustrating to see Biden now is throwing his weight behind a ceasefire when only a few weeks ago when the UN security council resolution was passed they were suggesting it was non-binding in some way. So actually America has allowed the ceasefire not to be brought in as comprehensively as it should be because they did not throw their weight behind it properly.” She added: “There is nothing anti-Israeli, much less antisemitic, in taking a tougher line with the Netanyahu government. The reality is that how Israel prosecutes this war, that is the problem we have. We support their right to self-defence but they are making themselves and us less safe in the way they are doing it.” Referring to the killing of World Central Kitchen workers this week, she said: “The Israeli military chain of command made the decisions that it was acceptable to kill six humanitarian workers and one operative. Humanitarian workers have protected special status under international humanitarian law.” Rejecting Israeli claims that the killings were a tragic error, she said the cars were clearly demarcated from the skies, the GPS coordinates had been provided and all three cars were struck in sequence. Kearns said Israeli attacks on humanitarian workers were “happening on a daily basis and we are not seeing this outcry when it is about Palestinian volunteers”. She also challenged Israel’s decision to bomb the Iranian diplomatic consulate in Damascus. “We need to be very cautious. The moment we or our allies break these rules, it makes all of us vulnerable, it makes our embassies vulnerable.” Kearns said Israel faced heinous enemies that the west wanted to help it defeat, but “some want to capture and create a monopoly of what it means to be a friend of Israel. There are attempts to stipulate the requirement to an unadulterated commitment to the Netanyahu government is what looks like friendship”. • Guardian Newsroom: Crisis in the Middle East On Tuesday 30 April, 7-8.15pm GMT, join Devika Bhat, Peter Beaumont, Emma Graham-Harrison and Ghaith Abdul-Ahad as they discuss the fast-developing crisis in the Middle East. Book tickets here or at theguardian.live