WASHINGTON — With congressional pressure mounting against the Bush administration’s military surge in Baghdad, Secretary of State Rice yesterday said America would be participating in a regional conference that would include Iran and Syria.

The announcement comes at the Senate Appropriations Committee’s first hearing to review the $99.6 billion that the White House is requesting to fund the troop surge in Iraq. It suggests that the Bush administration is making efforts to accommodate congressional Democrats, who have urged the president to send envoys to Damascus and Tehran to begin brokering an exit from Iraq.

The summit also represents a change in tone for the Bush administration, which has accentuated the threat posed particularly from Iran in recent weeks. Yesterday, at a hearing of the Senate’s intelligence committee, the new director of national intelligence, Mike McConnell, said some Shiite militia members received training in how to use armor-piercing explosives against American convoys inside Iran and in facilities run by Iran’s Lebanese proxy, Hezbollah.

While an administration official denied the announcement from Ms. Rice was motivated by politics, the secretary of state’s testimony pointed out how the new initiative reflected the wishes of the administration’s congressional critics.

“This is one of the key findings, of course, of the Iraq Study Group, and it is an important dimension that many in the Senate and in the Congress have brought to our attention, and I’ve had very fruitful discussions about how to do this,” Ms. Rice said. “So I’m pleased to inform you that the Iraqis are launching a new diplomatic initiative, which we are going to fully support.”

The Bush administration has not been averse to talking with Iran and Syria, as some of its critics contend. For example, in November 2005, the American ambassador to Iraq, Zalmay Khalilzad, announced his intentions to meet with his Iranian counterpart in Baghdad to create a formal channel between Iran, Iraq, and America. That month, the Arab League hosted a conference of Iraqi politicians to encourage participation in the December 15 elections.

The hope for next month’s conference — a final date needs to be set — is to create the framework for a group of Iraq’s neighbors, other big powers, and multilateral institutions. The March meeting in Baghdad will be held on a “subministerial level,” meaning the highest-ranking participants will be ambassadors as opposed to foreign ministers. But if the diplomacy goes well, then a follow-up meeting at the foreign minister level will be called, and Ms. Rice hinted yesterday that she would attend.

At the hearing, Ms. Rice said she did not know if Syria or Iran would accept the invitation from Iraq’s Foreign Ministry but that Senator Specter, a Republican of Pennsylvania, had assured her that both countries likely would participate. Recalling his recent meetings with Syria’s president and Iran’s ambassador to the United Nations, Mr. Specter conveyed their interest in such a regional meeting.

Within an hour of those remarks, news wires carried stories announcing that Iran and Syria intend to attend next month’s conference in Baghdad. Senator Hagel, a Republican of Nebraska, who may be the only potential anti-war candidate for his party’s presidential nomination, hailed the news that Iran and Syria would be represented at the upcoming parley. “This is an important diplomatic initiative taken by the Iraqi government,” he said. “We will not achieve peace and stability in Iraq without a regional framework that includes Iran and Syria. This conference can be an important first step towards creating that framework.”

But where Mr. Hagel was hopeful, the Senate’s majority leader, Senator Reid, a Democrat of Nevada, was skeptical.

“The Bush administration’s decision to begin talks with Iran and Syria should have been made long ago,” he said in a statement. “Democrats and the bipartisan Iraq Study Group have made clear for months that America must be willing to talk with all major nations in the region, including Iran and Syria, if we are ever to find the necessary political solution in Iraq. Today’s announcement is a first step, but it is not enough on its own.”

A Republican staffer in the Senate yesterday said his party’s leadership was caught unawares by the announcement yesterday.