President Bush moved on two fronts yesterday to ease the "staggering burden" on countries whose economies have been hurt by the Persian Gulf crisis, as the Pentagon sharply increased its estimate of the size of Iraqi forces in southern Iraq and Kuwait to 430,000.

On Capitol Hill, the House Appropriations Committee approved Bush's request for $1.9 billion in additional money to support Operation Desert Shield, marking the first major congressional action in support of the deployment.

But Bush suffered a setback when the committee, reflecting domestic political pressures, balked at the president's request to forgive Egypt's $7.1 billion military debt. Administration officials said they would continue the fight for the debt relief.

In a speech to the annual meeting of the World Bank and the International Monetary Fund, Bush announced the formation of an international unit to "turn commitments into contributions" for front-line states in the gulf most affected by the economic sanctions against Iraq.

"The staggering burden, which is pressing upon those most seriously affected countries, calls for a generous response from the world community," Bush said.

Earlier, after meeting with Turkish President Turgut Ozal, Bush pledged to open negotiations on a new textile agreement with Turkey, in recognition of Ozal's "steadfast" stand against Iraqi President Saddam Hussein's Aug. 2 invasion of Kuwait.

"Turkey has stood firm and steadfast despite the heavy burden the Iraqi invasion has placed on its own economy," Bush said.

Bush also said he would urge Congress not to slash military assistance to Turkey and promised to support Turkey's desire to join the European Community in the future.

Ozal, saying Turkey wants "more trade than aid" to help its economy, urged continued enforcement of the economic sanctions, adding that he still hoped for a peaceful solution to the gulf crisis.

Ozal, in an interview with Washington Post editors and reporters, said the sanctions have "a very high chance" of success and warned that war "has to be used as a last resort" because it would create enormous problems in the Arab world.

In his meeting with Bush, Ozal said he believed the Iraqi military had been overestimated by the rest of the world, according to James Dobbins, principal assistant secretary of state.

The new aid unit announced by Bush, called the Gulf Crisis Financial Coordination Group, will be headed by Treasury Secretary Nicholas F. Brady. Composed of major industrialized nations as well as wealthy gulf states such as Saudia Arabia and Kuwait, the group is designed to coordinate the flow of aid to the countries whose economies are most affected by the crisis.

Brady and Secretary of State James A. Baker III raised pledges of about $20 billion in recent trips, more than half of which will be used to pay for Operation Desert Shield.

Administration officials said the group, which will receive technical assistance from the World Bank and IMF, will assure equitable disbursement of funds.

The latest Defense Department estimates of Iraqi forces represent the arrival of new troops and the refinement of earlier estimates. The increase of 70,000 since last week includes 35,000 new troops, officials said.

Pentagon spokesman Pete Williams said that while there had been a further buildup of Iraqi forces near the Saudi Arabian border, "It is still essentially a defensive force, although it maintains a sufficient mechanized and armored division force level to launch a multi-corps attack with little warning."

The Iraqis, he said, also have added about 700 tanks, 700 armored personnel carriers and 250 artillery pieces to the region since last week. They now have 3,500 tanks, 2,500 personnel carriers and 1,700 artillery weapons in the area.

Separately, senior Defense Department officials said the Soviet Union still has 500 to 1,000 military advisers in Iraq, including many who are believed to be helping the Iraqi military maintain its warplanes.

The issue, they said, has provoked a major debate among top-ranking Soviet officials. At the Helsinki summit, Bush urged Soviet President Mikhail Gorbachev to withdraw the advisers immediately. Gorbachev refused, but said they numbered just 150. Pentagon officials said that figure represents only the advisers in uniform. The others are civilians.

In Congress, Bush faces difficulties winning support for Egyptian debt forgiveness. But the House committee, wishing to support President Hosni Mubarak, temporarily exempted Egypt from a law that prohibits new security assistance to countries that are more than a year in arrears on previous loans. Sources said Egypt would fall into that category in a few days.

Rep. David R. Obey (D-Wis.), chairman of the Appropriations subcommittee overseeing foreign aid, said it was "a lead pipe cinch" that the House would reject a blanket forgiveness of the loan.

A senior administration official said yesterday's action was "just the first shot. . . . There will be another and we are confident of success."

In a related matter, the House Foreign Affairs Committee is expected to approve today a joint congressional resolution on the gulf that supports the president's actions in sending troops to the area but avoids specific authorization for their use in military action.

The committee draft resolution, put together under the direction of Chairman Dante B. Fascell (D-Fla.), comes closest to the controversial question of authorizing force when it says, "The United States shall use, to the extent possible, diplomatic and other non-military means" to reach its objectives "while maintaining credible deterrent U.S. military forces."

Staff writers Ann Devroy, Dan Morgan and Walter Pincus contributed to this report.