Talking ahead of talks with US President George Bush, Blair on a visit to New York on Thursday also dismissed the significance of a message from al-Qaida leader Usama bin Ladin offering European states a truce.
"You know, I don’t think we need Usama bin Ladin to start telling us how to handle our political affairs," Bush said after talks with UN Secretary-General Kofi Annan.
Blair meets Bush on Friday in Washington, when they are likely to discuss their strategy in Iraq.
"Obviously the common aim and purpose is what is crucial," Blair said, adding this goal was to "create a stable and democratic Iraq, governed by the Iraqi people."
"And how we get there is obviously the difficult issue, particularly with the security at the moment, but our determination to get there remains undimmed. We have to stand firm," he said.
"You know, I don’t think we need Usama bin Ladin to start telling us how to handle our political affairs"
UK Prime Minister
"If people are killing innocent civilians we have got to deal with that," Blair said.
The prime minister also said he saw no disruptiion to the Middle East 'road map' for peace despite the Israeli Prime Minister Aerial Sharon's plans for a selective withdrawal from some Palestinian territory.
"I don't see the road map as sidelined at all," Blair said. "Until progress is made on the now stalled road map, the international community would inevitably look to other measures in the meantime to move the issue forward, he said.
Meanwhile, the UN Secretary-General said that any steps taken by Israel should not preempt so-called final status questions such as the eventual borders of a Palestinian state.
"The withdrawal from Gaza should be seen as a first step because we also have to deal with the issue of the West Bank," Annan said.
"Any initiative that is taken to influence the situation should not preclude the future status issues which have to be settled between the two parties," he added.