David Cameron is coming under pressure to recall Parliament amid growing unrest at the humanitarian crisis engulfing Iraq.
With more reports of slaughter of minority Christians and Yazidis by Islamic State (IS) extremists in the north of the country, a Tory backbencher has insisted the Commons needs to debate military action.
Conor Burns said the Government's response so far, of ruling out military intervention and airdropping supplies, was "not strong enough".
"I feel very strongly about this," the Bournemouth West MP said. "I have been following this really closely for the last couple of weeks but having seen some of the images earlier I was quite seriously overcome.
"These are brother and sister Christians, and this is happening to them in no small part because of our record in Iraq.
"I feel very strongly that the Government's response is not hard enough or strong enough.
"These people are being beheaded by people from IS, and our only response is to drop some food or water on them.
"I think the US and UK should be involved in air strikes. I am not by any means advocating a ground war but I think we should put our special forces in there.
"I think we should be answering positively requests from the Kurds to arm them. I think we should be looking at asylum."
Mr Burns said he did not know whether the Commons would support military action, but it was "worth trying" - adding that some Conservative colleagues who opposed intervention in Syria last summer took a different position this time.
"Some of this was created by us in the first place, and I do not think it is right just to say we cannot do this or public opinion doesn't support it," he said.
"I think the Syria thing and this are very different.
"If Parliament decides we do not want to have anything to do with that, then let them say so."
The former head of the army, Lord Dannatt, also backed a recall, insisting Britain was "watching in horror" as atrocities were committed.
"In the face of a crisis of this scale, with the potential for so much human misery, this is not the moment for decision-makers to be on holiday. Parliament needs to be recalled and the West needs to face up to its responsibilities," he wrote in the Sunday Telegraph.
Earlier, Downing Street announced that more UK advisers were being sent to the under-threat city of Irbil to help deal with the developing crisis.
The US has been carrying out airstrikes to protect the area, which is a Kurdish stronghold and major centre for the country's oil trade.
After a meeting of the Government's Cobra emergency committee attended by officials from across Whitehall and agencies, a Number 10 spokesman said: "The humanitarian situation remains deeply worrying and consequently this continues to be our priority.
"Hundreds of thousands of people are displaced across the region and in need of aid supplies. And thousands are still trapped on Mount Sinjar, although it is understood that some may have escaped off the mountain to the north.
"The first UK aid drop took place over Mount Sinjar last night, with the RAF delivering bundles that included 1,200 reusable water containers providing 6,000 litres in total and 240 solar lanterns that can also be used to recharge mobile phones.
"We are working to step up these deliveries in the coming days. Meanwhile, we continue to engage with the US, Kurds, Turks and other international partners on how to get those trapped on the mountain to safety.
"And we are planning to increase the number of humanitarian advisers in Irbil to provide better links to the situation on the ground.
"We continue to urge Iraqi political leaders to appoint a prime minister who can lead an inclusive government.
"This is vital to ensure that Iraqis themselves are able to co-ordinate the response across the country against ISIS, uniting all Iraqi communities against these evil terrorists."
The Government announced an £8 million emergency package last week, £3 million of which will go to charities and NGOs already on the ground and helping displaced people in northern Iraq, and £2.5 million to the International Committee of the Red Cross.
Mr Cameron and US president Barack Obama discussed the airdrops in a phone call yesterday, but admitted that a "long term solution" would be needed to quell the IS advance.
Tory former minister Alistair Burt told BBC Radio 4's The Westminster Hour that there "may be a need to arm the Kurdish fighters rather more intensively".
"I don't think there's any need to recall Parliament unless the Prime Minister wants to move on from humanitarian aid," he said.
"If he does and wants support, I think Parliament should give it to him.
"I think we should be in no doubt whose side we're on. We should support the Kurdish regional government and the Iraqis and any force that is prepared to deal with IS and the threat they pose to the stability in the region."