Nick Clegg has accused Labour of a "distasteful" attempt to make political capital from the Mediterranean refugee crisis.
It follows a row over a speech by Ed Miliband in which he is due to suggest the deaths of hundreds fleeing North Africa are "in part a direct result" of the government's military intervention in Libya in 2011.
Mr Clegg told BBC Radio 5 Live it was "pretty distasteful to reduce this total human tragedy, hundreds of people dying in the Mediterranean, to a political point-scoring blame game".
But he acknowledged that it was "legitimate to say that things then spiral in directions that you can't fully predict".
"All I would plead for is a little less finger-pointing wisdom from Ed Miliband - when he supported the intervention in the first place - and a little bit more adherence to facts about exactly who is ending up on these boats, why they are and what we can now do about it to stop this terrible tragedy," he said.
Nicola Sturgeon has pledged that SNP MPs at Westminster will work to deliver a "better, fairer deal" for Scotland's 100,000 carers.
Scotland's First Minister said: "It is simply unfair that carers do not receive the same support as those looking for work. That's why the SNP will use our influence at Westminster to put carers firmly on the Westminster agenda, securing an increase in carers' allowance benefiting carers to the tune of £600 per year.
"We will never be able to do enough to fully recognise the incredible work our carers do. But carers in Scotland - and across the UK - can be confident that the SNP will be a strong voice for their interests in the House of Commons.
A Survation poll for the Daily Mirror has seen Labour dropping four points to 29% but the Conservatives do not appear to have benefited, also dropping one point to 33%.
The Liberal Democrats, however, jumped three points to 10%, while Ukip put on one point to reach 18%. The Scottish National Party was unchanged on 4% and Greens up a point to 4%.
The Environment Secretary Liz Truss has said it is "absolutely offensive" for Ed Miliband to imply David Cameron has some role "directly or indirectly" for the recent deaths of migrants in the Mediterranean.
In a foreign policy speech later today, the Labour leader is expected criticise the prime minister for the ”failure of post-conflict planning” after the fall of the Gaddafi regime in Libya.
The ongoing instability in the country has been blamed for the boom of people-trafficking crossing from Libya to the Mediterranean and the subsequent increase in migrant deaths on these boats.
Ms Truss said: "To bring this into an election campaign I think is outrageous and disgraceful.
"Actually accusing the Prime Minister of causing these deaths - whether directly or indirectly - I think is wrong."
"Of course we should be talking about foreign affairs but it has to be done in a proper manner", she added.
A minority government led by Labour or the Tories would spell economic disaster and could cost the average homeowner £800 a year, the Liberal Democrats have claimed .
In a speech, Chief Secretary to the Treasury Danny Alexander will say "An unstable government, unable to take serious decisions, pulled sharply to left or right, with Alex Salmond or Nigel Farage, would cost us all dear. It would jam the brakes on the economic recovery."
"As the market commentary makes clear, such an outcome would lead to higher costs of government borrowing, mortgage costs rising by at least an estimated £800 a year, and a weaker pound.
"That would be an economic disaster for Britain, and an insult to the massive effort and the many sacrifices made by millions of people and businesses who are powering our recovery.
We are the only party that can keep Britain in the centre ground, the markets happy and the recovery going."
When asked again today whether Labour would enter a formal coalition with the Scottish Nationalists to form a government, Ed Miliband repeated that it wouldn't happen.
However, the Labour leader did stop short of ruling out some sort of post-election pact, should his party fail to win a majority.
Meanwhile, SNP leader Nicola Sturgeon repeated her call for Labour to join forces, saying that only together could they lock the Tories out of Downing Street.
ITV News Deputy Political Editor Chris Ship reports:
David Cameron has launched the Scottish Conservative manifesto in Glasgow.
He kicked off the event with critical comments against Labour and the Scottish National Party and the prospect of a Labour-SNP coalition.
Mr Cameron said that the two parties “pose a clear threat to the future of the UK,” calling a potential alliance between Labour and the SNP a “coalition of chaos”.
Ukip MEP, Diane James, has said she admires Russian President Vladimir Putin because he is a "very nationalist" leader who was "standing up for his country".
In remarks that echo Ukip leader Nigel Farage's naming of Mr Putin as the world leader he most admired for his "brilliant" handling of the civil war in Syria, Ms James also lauded him for the way he reacted to perceived intervention by the European Union.
Ms James, who recently withdrew as Ukip's General Election candidate in North West Hampshire for family reasons, was taking part in an all-female debate on LBC radio after Ukip deputy chairman Suzanne Evans lost her voice.
I admire him from the point of view that he's standing up for his country. He's very nationalist I do admire him. He is a very strong leader.
He is putting Russia first and he has issues with how the EU encouraged a change of government in the Ukraine, which he felt put at risk and put in danger a Russian population in that country."
Asked by GQ magazine last year which leader he most admired, Mr Farage said: "As an operator, but not as a human being, I would say Putin. The way he played the whole Syria thing. Brilliant. Not that I approve of him politically. How many journalists in jail now?"
While stressing that he did not approve of Mr Putin's annexation of Crimea, he said EU leaders had been "weak and vain", adding: "If you poke the Russian bear with a stick he will respond."
In Wales the leader of Plaid Cymru Leanne Wood claimed the election offered an "unprecedented" opportunity at the launch of her party's manifesto.
In an interview with The Sunday Telegraph David Cameron has set out a series of policies designed to appeal to traditional Tory voters.Read the full story ›