WASHINGTON — President Bush telephoned the besieged U.S. Embassy in Kuwait on Wednesday to encourage the ambassador and his skeleton staff to hang on under “most difficult circumstances.” Separately, Bush told lawmakers he would consider further moves if economic pressure fails to push Iraqi forces from Kuwait.

Meanwhile, the White House brushed off Iraqi President Saddam Hussein’s statement that “the children of Iraq are dying” because of the U.N.-supported economic embargo. Presidential spokesman Marlin Fitzwater said there was no evidence to support the statement and dismissed it as simply “another rhetorical diatribe.”

Bush, who met privately with more than 30 senators and House members, will address a joint session of Congress next Tuesday night after returning from his weekend summit meeting with Soviet President Mikhail S. Gorbachev, Fitzwater said.

At the Capitol on Wednesday, Secretary of State James A. Baker III wound up a second day of congressional questioning — repeating his proposal for planning a new “regional security structure” for the Middle East — and was leaving Wednesday night for Saudi Arabia.

He said again that Americans should not expect any quick resolution of the standoff which has brought tens of thousands of U.S. troops to the Saudi desert to face an even larger force of Iraqis across the Kuwaiti border.

Current U.S. efforts, aimed at weakening Saddam’s resolve through the economic embargo, “are going to take some time, and that is what we ask most of the American people: Stand firm, be patient and remain united so that together we can show that aggression does not pay,” Baker told the Senate Foreign Relations Committee.

However the current situation plays out, he said, “this is not the last crisis of this nature we are likely to face in this region. … It is worthwhile to begin considering regional security structures … that would guarantee an equilibrium in this region that will produce peace” and “create a more durable order.” He gave no details and said such planning was in a very early stage.

Meanwhile, Prince Bandar bin Sultan, the Saudi ambassador to the United States, sent letters to each member of Congress expressing his country’s gratitude for lawmakers’ support of Operation Desert Shield.

“I want to convey our regard and respect for the individual men and women of the American air, naval and ground units now temporarily in Saudi Arabia and the adjoining waters, side by side with our own defense forces and those from a number of important Arab, European and other countries vigilantly there,” he said.

In one military development, the Navy said it had authorized the battleship USS Wisconsin in the Persian Gulf to fire its 16-inch guns, which had been silenced in May after an investigation was reopened into the deadly explosion aboard the Wisconsin’s sister ship, the USS Iowa.

Navy spokesman Cmdr. Jim Mitchell said additional tests had “determined that the 16-inch guns may safely fire specified lots of powder, which are now loaded on the Wisconsin.”

Baker’s overseas trip, which also will include the weekend U.S.-Soviet summit in Helsinki and later stops in Europe, will focus partly on soliciting contributions to help pay for the military effort opposing Saddam. Another Cabinet member, Treasury Secretary Nicholas Brady, was on his way to South Korea Wednesday after winning a pledge of support from Margaret Thatcher in London.

At the White House, Fitzwater said Bush called the embassy in Kuwait City to express his appreciation to Ambassador Nathaniel Howell and the few other staff members who stayed behind to assist Americans trapped in the region.

Iraq has cut off water and electricity to the embassy as part of its effort to shut down all foreign embassies in the land it annexed after its Aug. 2 lightning invasion.

Bush told his envoy “to keep up the good work under these most difficult circumstances,” Fitzwater said.

“Ambassador Howell is struggling with a very difficult situation in terms of the physical conditions there. They have fast-diminishing supplies of water and electricity. But as you all know and have seen on the television reports, the embassy staff there has been actively working with U.S. citizens in helping to facilitate these flights out of Kuwait and out of Iraq,” the spokesman said.

Later on Wednesday, Bush met with more than 30 members of Congress concerning the Persian Gulf crisis.

Bush told them that “we must keep pressure on Iraq and convince Saddam Hussein that time is against him,” Fitzwater said. “The president said, `The sanctions must succeed. If not, we will review our options.”‘ The spokesman would not elaborate.

The lawmakers gave Bush “repeated statements of support to see this mission through,” Fitzwater said. They also had suggestions for the president they indicated in comments after the meeting. In some of them:

Sen. John Glenn, D-Ohio, said the U.S. troops stationed in the Saudi Arabian desert might be given pay and income tax incentives “to forestall a morale problem.” Glenn, part of a congressional delegation just back from the Middle East, said he also suggested such benefits as free postage stamps for the troops.

Glenn also suggested going beyond the current sea blockade by imposing sanctions against countries where planes take off to carry cargo to Iraq.

Sen. William Cohen, R-Maine, said Bush should push Soviet President Mikhail S. Gorbachev during this weekend’s summit meeting to pull remaining Soviet military and technical advisers out of Iraq. He said Bush should not accept the “fig-leaf excuse” that the advisers are there on unexpired contracts.

Sen. John Kerry, D-Mass., said he urged Bush to press the Soviets for intelligence material on the Iraqi military capability.

Fitzwater praised the Soviet Union’s role in the international effort to isolate Iraq.