LONDON - The Liberal Democrats called for United Kingdom (UK) arms exports to Israel to be suspended on Wednesday morning.

The British government is under pressure from Tory MPs and peers to stop arming Israel after seven humanitarian aid workers were killed by an Israeli airstrike in Gaza.

Three Conservatives told the Guardian on Wednesday that the UK should stop exporting arms to Israel following the strike, which killed three British aid workers.

Their intervention comes after Peter Ricketts, who was a government national security adviser during David Cameron’s premiership, said the “time has come” to send a signal and stop exporting arms.

David Jones, the Conservative MP for Clwyd West, said the Israeli strike on the aid convoy was “extraordinary”.

“The government should urgently reassess its supply of arms and deliver a stern warning to Israel about its conduct. Israel has every right to defend itself and every right to act proportionately – that doesn’t include people who are trying to do good,” he said.

“Given that we’ve seen three British citizens – all of them ex-forces – killed in what is, at best, a negligent manner I think that we really need to reassess our supply of weaponry there.

“I thought that [Benjamin] Netanyahu’s response – ‘these things happen in war’ – was completely inadequate, frankly shamefully inadequate.”

Flick Drummond, the Conservative MP for Meon Valley, said UK arms sales to Israel should be stopped “for the foreseeable future”.

“This has been concerning me for some time,” she said. “What worries me is the prospect of UK arms being used in Israel’s actions in Gaza, which I believe have broken international law.”

Hugo Swire, a former Foreign Office minister in Cameron’s government, said: “I fully support the UK policy of selling arms to Israel in order for Israel to be able to defend herself from any would-be aggressor. What I do not support is the selling of arms which can be – and now look as if they are being – used offensively in Gaza.”

Lord Ricketts, who is also a former permanent secretary of the Foreign Office, told BBC Radio 4’s Today programme: “I think there’s abundant evidence now that Israel hasn’t been taking enough care to fulfil its obligations on the safety of civilians. And a country that gets arms from the UK has to comply with international humanitarian law. That’s a condition of the arms export licence. So honestly, I think the time has come to send that signal.

“It won’t change the course of the war. It would be a powerful political message. And it might just stimulate debate in the US as well, which would be the real gamechanger.”

The seven aid workers, who had been delivering food aid to Gaza, were killed on Tuesday by an Israeli drone. Those killed – three British citizens, a Palestinian, a US-Canadian dual citizen, a Pole and an Australian – were working for World Central Kitchen (WCK), an international charity.

The former Conservative Foreign Office minister Alistair Burt also said there was now a higher chance that the UK might suspend arms sales to Israel, telling the BBC’s The World Tonight programme on Tuesday that it would send a clear signal “that there’s a point beyond which the UK simply cannot go”.

Rishi Sunak has called for an urgent investigation into the Israeli airstrike.

The seven victims were named by WCK as Britons John Chapman, 57, James Henderson, 33, and James Kirby, 47, who were working for the charity’s security team. The team’s leader, Lalzawmi (Zomi) Frankcom, 43, an Australian national, also died, along with American-Canadian dual citizen Jacob Flickinger, 33, Polish national Damian Sobol, 35, and Palestinian Saif Issam Abu Taha, 25.

On Tuesday the Israeli newspaper Haaretz published details of the strike, citing defence sources. According to the report, an Israeli drone fired three missiles at the convoy of three armoured cars – all of which were clearly marked on the roof and sides with the WCK’s logo – because of a suspicion that an armed militant was travelling with them.

Despite the fact that the suspect did not leave a warehouse with the rest of the group, the cars were hit as they travelled back along a route pre-approved and coordinated with the Israel Defense Forces (IDF), the report said.

Lt Gen Herzi Halevi, the chief of the general staff of the IDF, said the incident was “a mistake that followed a misidentification –during a war in very complex conditions. It shouldn’t have happened”.