The Prime Minister said the current massacres had been planned by Yugoslav President Slobodan Milosevic over the last two months.
In a statement to the House of Commons, Mr Blair said: "For every act of barbarity, every slaughter of the innocents, Milosevic should be made to pay a higher and higher price."
He made clear that the air strikes were continuing and intensifying amid the renewed Serb repression in Kosovo.
"It is now clear that Serb participation in the Paris peace talks was a cover for Milosevic's offensive preparations.
"In my view, our response to these appalling acts, far from halting or slowing the allied action, must be to intensify it and see it through to a successful conclusion," he said.
Addressing backbench concern over the military action, he said that no one who had seen the "utter, callous brutality" with which the Kosovo Albanian people had been treated was under "any remaining illusions about the nature of the Serb regime".
Mr Blair disclosed that the Department for International Development had allocated an extra pounds 10m to an international refugee relief effort, and a joint military and civilian team would visit Macedonia and Albania later this week.
William Hague, the Tory leader, reiterated his party's support for the military action. "Nothing would be more disastrous to the humanitarian situation you have described or to the credibility of Nato than if we backed out of what has now been started," he said.
Paddy Ashdown, the Liberal Democrat leader, called for "whatever was needed" - including the use of ground troops - to cope with the humanitarian crisis, not just for "reasons of humanity but also for reasons of stability".
He added: "Is it not the case if the voice of the Kosovo Albanians were heard in this chamber they would be saying: `For God's sake don't stop until the job is done'?"
But David Davis, the former Tory Minister for Europe, challenged the Prime Minister: "Could you tell us whether you predicted Milosevic's viciousness and, if you did, why was not more of the immediate military action focused on mitigating it?"
Tony Benn, the Labour MP who has led opposition to the air strikes in the Commons, argued that the refugee situation had deteriorated as a result and could destabilise the region.
"What is required is UN action, a ceasefire, of the kind you urged so skillfully in Northern Ireland, and bringing in somebody of international status, maybe Nelson Mandela, to try to get the sides together before the situation gets totally out of control," he said.
Tory Sir Peter Tapsell, dismissed Britain's involvement in the air strikes as "historically ignorant, politically inept and internationally illegal".Reuse content