Sen. John Kerry (search) blasted President Bush Thursday, saying the commander in chief needs to speak truthfully to the American people and say that his administration was not prepared for the post-Operation Iraqi Freedom (search) cleanup.

"It's time for the president to tell the truth -- that we lack sufficient forces to do the job of reconstruction in Iraq and withdraw in a reasonable period, to tell the truth that America should not go it alone," the Massachusetts Democrat said in an abruptly called press conference on Capitol Hill.

Kerry, who voted in support of a war resolution for Iraq, said that U.S. casualties continue to mount, but he did not draw any analogies between Iraq and Vietnam (search), in which he served in the Navy. He did criticize the president for failing to draw on international support for the war.

"One of the reasons I'm running for president is to hold this president accountable for the lack of planning, the lack of diplomacy, the lack of strategy, the lack of commitment to multilateral institutions that have allowed America to be strong," he said.

Kerry did say that if the United States is going to keep its commitment to Iraq, a few "key steps" must be taken to win the peace, including increasing overall troop strength, especially with allied troops; training Iraqi troops to carry out the job of restoring order; and laying out an immediate and clear plan for the transfer of power to the Iraqis.

Since major combat ended on May 1, 70 U.S. troops have died in hostile action and accidents in Iraq. President Bush and former U.S. Central Command head Gen. Tommy Franks both said Thursday that the United States will persevere. Franks added that U.S. troops will likely be in Iraq for at least a year.

But Kerry, who according to news reports hadn't planned on revving up his presidential campaign until the fall, came out swinging on Thursday. He said he wants an "open, thorough, complete and absolutely believable investigation into the quality of American intelligence," particularly intelligence that led the president to announce wrongly in his January State of the Union address that Iraq was attempting to acquire uranium from Niger.

The White House admitted this week that the intelligence, obtained from British reports, was based on forged documents.

"We now know [that Bush's State of the Union address] contained information that was wrong -- and at least some in the administration knew," Kerry said. "But just because a mistake was made, we should not compound it by making further mistakes."

Later in the day, Kerry addressed 3,000 members of the American Federation of Teachers, to talk about his vision for educating America's children. Billed as a major address on education, he did touch on things like his vision of smaller classes and his disdain for the idea of school vouchers, but most of his speech was again aimed at Bush.

"I say to you, my friends, I cannot wait to criss-cross this country, and I will hold this president accountable for making a mockery of the words, 'leave no child behind.' We will have accountability," he said. 

Political experts say Kerry's turning up the heat on the president is a sure sign that he is feeling the pressure from his rival, former Vermont Gov. Howard Dean. Dean's been getting good buzz in Democratic circles for his fund-raising prowess and his willingness to tangle with a very popular incumbent president.

Dean has surprised many by raising $7.5 million between April and June. But he is also spending money at a faster pace than any of the other eight Democratic candidates, buying expensive airtime in Iowa. By some estimates, he's got about $6 million left in the bank. Kerry, on the other hand, has about $11 million in the bank.

The Kerry campaign won't acknowledge any concern about Dean, who is running neck-in-neck against Kerry in New Hampshire. One Kerry campaign staffer recently told a national magazine, "We can take Howard Dean out whenever we want to. Why do it now?"

The rest of the Democratic pack, including Connecticut Sen. Joseph Lieberman and Missouri Rep. Dick Gephardt, seem content to let Dean and Kerry fight it out, figuring that by the time the New Hampshire primary is over next January, only one of the two will still be standing strong.

Fox News' Brian Wilson and Julie Asher contributed to this report.