Britain is deploying RAF Tornado jets to provide greater surveillance of northern Iraq after being forced to abort two attempts to drop aid for Yazidi refugees on Mount Sinjar amid fears that the cargo could have injured people on the ground.

Amid growing calls for a recall of parliament to allow Britain to join the US in launching air strikes against forces from the Islamic State (Isis), Downing Street announced an intensification of British involvement with the deployment of the Tornadoes to the region.

Officials made it clear that the Tornadoes, whose actual deployment over Iraq has yet to be agreed by ministers, would be used solely for surveillance to avoid a repeat of Sunday night, when the crew of an RAF C-130 Hercules aircraft had to abort their mission to avoid injuring refugees on the ground.

British crews on Monday night followed up with greater success, with the RAF able to deliver "essential supplies" over Mount Sinjar to assist the Yazidis, the Department for International Development (DfID) said.

There have been reports of US air drops having mixed results after refugees reported that food packages disintegrated because they were distributed from high altitude.

Philip Hammond, the foreign secretary, who chaired a meeting of the government's emergency Cobra committee, insisted that Britain was only providing humanitarian support and would not join the US in launching military strikes against Isis forces. Downing Street indicated that Britain may be prepared to follow the example of the US in arming Kurdish forces that are fighting Isis, though the prime minister's spokeswoman said that no decision had been taken.

But a cross-party coalition of MPs, led by the former Labour foreign secretary Jack Straw and the former Tory armed forces minister Andrew Robathan, is calling for Britain to join the US strikes against the Islamic State forces.

Straw, who said that parliament may have to be called to discuss the Iraq crisis, told ITV News: "I hope that the British government are now accelerating their humanitarian intervention and assistance. It's taking a bit of time to get going and these poor devils are dying at the moment.

"They have to look at what further action we could take by way of military assistance. Not talking about boots on the ground, there are other things we could do. One way or another, these maniacs, these medieval maniacs, in the so-called Islamic State, have got to be defeated."

Robathan said that Britain would have to be involved in military strikes if it wanted to defeat Isis forces. He told the World at One on BBC Radio 4: "There can be no real help for the people of Iraq that are threatened by [Isis] without stopping [its] advance. That is what anybody who is worried about the humanitarian situation has to admit.

"We have to realise it is no good just sending aid. The real solution is to stop these people and hopefully allow the Iraqis and the Kurds to defeat them. There are many ways one could use military strikes – air strikes or the use of drones can be done fairly surgically without putting troops on the ground. We had our fingers pretty badly burnt in Iraq, as did the Americans.

"There is no appetite to have proper troops on the ground. However, the idea of a few observers perhaps directing air operations is a slightly different matter."

Downing Street joined Hammond in ruling out British military involvement though the prime minister's spokeswoman indicated that Britain may be willing to follow the example of the US in arming Kurdish forces. The spokeswoman said: "Our focus is on the humanitarian effort. We do think it is important that the Iraqi forces, including the Kurdish forces, are able to respond to Isil [Isis] and to tackle this crisis. So we will look at what options there are that might enable them to do that. But there have not been discussions, substantive discussions, of that yet. There are certainly no decisions."

If ministers approve the deployment of the Tornadoes over Iraq they will be used for surveillance over the north of the country to assess the needs of the refugees and to avoid a repeat of Sunday night, when the RAF crew feared they could injure people on the ground. The Tornadoes are able to film the ground. Officials believe they could deal with any threat with electronic jamming equipment.

The RAF had been trying to drop water. On Saturday Britain dropped 1,200 reusable water containers providing 6,000 litres of water and 240 solar lanterns, which can be used to recharge mobile phones. The solar lanterns are crucial in helping Britain and the US communicate with people on the ground. Britain hopes to drop shelter kits when it resumes the aid flights.

The prime minister has ruled out British military involvement in Iraq amid strong public resistance to renewed action. Cameron was also bruised when he recalled parliament during last summer's recess to approve military action against Bashar al-Assad after the Syrian regime's chemical weapons attacks on a Damascus suburb. The prime minister was defeated after a Tory rebellion and the refusal of Ed Miliband to agree to an amended government motion. Cameron decided after the vote that it would be all but impossible to secure the support of MPs for military action in this parliament.

The decision to deploy the Tornados to the region came as Britain proposed a UN security council resolution to punish the recruitment and financing of fighters for Isis. An early draft of the resolution, seen by the Associated Press, says that "widespread or systematic attacks directed against any civilian populations because of their ethnic background, religion or belief may constitute a crime against humanity."