Saudi Arabia, its enormous cash reserves depleted by the cost of the Persian Gulf War, may seek large loans for the first time from international banks, knowledgeable diplomatic sources in Saudi Arabia said yesterday.

The strain on Saudi finances has arisen because of war-related expenditures and pledges of support totaling $48 billion -- half the kingdom's annual income -- made since Iraq invaded Kuwait last Aug. 2. The largest single portion of this extraordinary outpouring of funds went to the United States, which was promised $13.5 billion for the first quarter of this year alone.

"It's an immense and very heavy burden that they've taken on," an informed diplomat observed. "And it increases as the war drags on."

The costs of the war are also sparking controversy for Kuwait's government in exile as it debates how best to manage its sizable assets and still come up with enough cash to pay for some of the war costs and promises of aid.

In December, a dozen managers at the Kuwait Investment Authority resigned, including the authority's assistant general manager, Salah Maousherji. A former Kuwaiti investment adviser said the resignations were prompted by a dispute over whether the managers had been consulted about decisions to liquidate Kuwaiti equity holdings overseas to pay for Kuwait's share of the war costs.

The London-based investment authority had about $100 billion at the start of the war.

Saudi Arabia's apparent need to borrow abroad less than one month into Operation Desert Storm has been cited as a reason for finishing the conflict as quickly as possible, the sources pointed out. But the pinch has not prompted King Fahd, the Saudi monarch, to push President Bush to accelerate the timetable beyond what is militarily prudent for starting a ground offensive to expel Iraqi troops from Kuwait, they said.

Analysts in Saudi Arabia and the United States agree that neither Saudi Arabia nor the exiled Kuwaitis appear to have a long-term liquidity problem. Sharif Ghalib, a specialist on Africa and the Middle East at the Institute of International Finance, said that "there is a potential for borrowing" by both.

But he noted that Saudi Arabia's international reserve holdings have tended to be invested in highly liquid assets, such as U.S. government securities. The availability of such holdings would make it unlikely that the kingdom would need to borrow funds because of liquidity problems.

One investment banker said he had inquired about arranging loans for Saudi Arabia by using Saudi-owned U.S. Treasury securities as collateral -- a simple, low-cost way of borrowing money that would be difficult for anyone not directly involved in the transaction to detect. But the investment banker was told that the Saudis were not seeking money.

However, this week the Federal Reserve notified its primary dealers that it will be arranging the sale of government securities to raise cash on behalf of unidentified foreign official institutions. Saudi government institutions are among the biggest holders of U.S. government securities. The announcement is a departure from usual practice by the Fed, which acts as the agent for foreign central banks in U.S. government securities markets. Usually the Fed will purchase the government securities itself at the request of the foreign governments.

It is unclear just how large Saudi Arabia's foreign reserve holdings are, or whether they have been drawn down significantly in order to pay the kingdom's bills. At the end of 1989, the Saudi government had $60 billion to $70 billion in foreign reserves, though the royal family's holdings could amount to tens of billions of dollars more. Of the government foreign reserve holdings at that time, there might have been only $25 billion to $30 billion in liquid assets overseas, according to analysts.

There are, however, signs that the kingdom is hesitating to embark on costly projects that do not deal directly with the war effort. For example, Saudi authorities have moved slowly to clean up a massive oil spill caused by Iraq in the northern Persian Gulf. Most offers of help in the cleanup have been based on the assumption that Saudi Arabia would foot the bill, and this suddenly has become difficult for the normally brimming Saudi treasury, the sources reported.

"They don't seem to have the wherewithal at the moment to do it," the diplomat said. "They don't have the money. That's an important incentive to minimize the problem."

Another sign of the strain came last weekend when British Secretary Douglas Hurd received only what were described as "helpful assurances" after a meeting with Fahd during which Hurd sought additional Saudi assistance to offset the cost of British forces here in the anti-Iraq coalition.

Emir Jabir Ahmed Sabah of Kuwait, by contrast, pledged to give Britain another $1.2 billion when Hurd visited the Kuwaiti government's exile headquarters at Taif, Saudi Arabia.

The former Kuwaiti financial adviser said that, considering the state of the world economy and the Kuwaitis' unique problem at the moment, it would be a "sensible approach" to borrow some money to finance war costs, instead of selling off holdings.

"You want to liquidate when the market is more favorable," he said. "It can be cheaper to borrow than to liquidate {holdings} during a recession. Plus, selling holdings could add a great deal of damage to markets as well."

Last month, Kuwait pledged $11 billion to cover war costs. Last year, it had pledged a total of $5 billion, half for the U.S. and half to other nations harmed by the conflict.

Despite the Saudis' hesitation to make new financial commitments, the Saudi royal family was expected eventually to provide additional funding for British forces, and it has yet to turn down any U.S. request for money in connection with the war effort.

"Everything the U.S. has asked for, the Saudis have committed, sometimes with an audible gulp, but they have met every request," a well-informed diplomat said.

The swift rise in oil prices to nearly $40 last fall as the threat of war hung over the region, as well as a rise in Saudi oil production to more than 8 million barrels a day, have provided the kingdom with a revenue increase of more than $12 billion.

In more recent days, however, the price of oil has sunk almost back to prewar levels and now sells for about $20 a barrel, reducing Saudi Arabia's extra cash intake by almost half.

Saudi expenditures and pledges, some of them decided last fall during the period of high oil prices, have included large amounts of cash support for the financially strapped governments of Egypt and Syria -- two important Arab members of the anti-Iraq coalition -- as well as the U.S. pledge and $12 billion of its own military outlays connected to the war, the sources explained.

The Saudi government also has paid out or contracted $16 billion for civilian work or supplies supporting the war effort, the sources said. For instance, Saudi Arabia has picked up the bills for much trucking of supplies, all fuel for U.S. and allied warplanes and vehicles and construction of new facilities for the roughly 700,000 foreign military personnel in the Persian Gulf region.

With the world's largest proven oil reserves, Saudi Arabia's cash-flow difficulties do not mean it has any long-term financial difficulties. "In the long run, everybody knows Saudi Arabia has been rich and will be rich," a diplomat said. "But it's got some financial problems for the moment."

At the same time, the possibility that Saudi Arabia will seek loans from private international banks was seen as a dramatic measure of the importance the kingdom attaches to the war. But it also represented a warning that more troubles could arise if the war turns into a drawn-out conflict requiring extended U.S. and other foreign participation.

Although the Saudi cash-reserve troubles have been common knowledge among Riyadh's diplomatic community, they have not been discussed publicly by the Saudi government. On one hand, a source pointed out, a government about to seek a loan would be ill advised to advertise any financial problems. On the other, he said, the Saudi government has always closely guarded information about finances and other government activities.

Saudi Arabia's cash reserves seemed boundless during the 1970s oil boom. But they declined during the last decade as oil prices fell and the kingdom spent lavishly to hoist itself into the modern era in a single generation. By the beginning of last year, the reserves had fallen to about $10 billion and were gradually eaten away as expenditures mounted last fall following Iraq's invasion of Kuwait.

Saudi Arabia also spent generously on foreign aid, granting about $93 billion between 1973 and 1990, mainly to Islamic countries. The outlays, about 6 percent of gross national product in some years, made the kingdom second only to the United States in the overall aid level and highest in the world in its per-capita aid level.

Cody reported from Riyadh, Saudi Arabia. Mufson reported from Washington.