Iraq has embarked on a campaign to soften U.S. public opinion on the Persian Gulf crisis by allowing letters and telephone calls from American hostages to reach their families, and inviting hostages' wives to visit their loved ones at Christmas.

Experts on Iraq and State Department officials said yesterday that Iraqi President Saddam Hussein has made a calculated effort to "tug at people's heartstrings," as one official put it, by allowing and promoting access to the hostages.

Since its Aug. 2 invasion of Kuwait, Iraq has permitted 269 letters written by American hostages held at strategic sites as "human shields" to be sent through the Iraqi Ministry of Foreign Affairs to the U.S. Embassy in Baghdad, which then sends them in a diplomatic pouch to the State Department here. From there, they are passed unopened to families throughout the country.

This weekend Iraq permitted 21 hostages to phone home, the State Department said yesterday, and an Iraqi relief official promised that hostages may send and receive regular mail beginning Nov. 15. Days before, Saddam allowed reporters to interview some captives.

"He is trying to accentuate and mobilize and personalize the situation of the hostages as he becomes more worried about the potential of a {military} conflict," said Jerrold Post, professor of psychiatry, political psychology and international affairs at George Washington University. "To the extent he can make them more flesh and blood human beings, it starts raising pressure against military action."

Another 358 letters written by families in the United States have been sent to hostages in Iraq through the State Department's diplomatic pouch and at least a few of them have gotten through, as evidenced by hostages' letters acknowledging their receipt, the State Department official said.

Letters also have been brought out of Iraq by released American and European hostages, apparently with the acquiescence of the Iraqi authorities, who could have easily confiscated such material.

While the U.S. embassies in Kuwait City and Baghdad continue to send and receive some electronic and telephone communication, the letters and calls are the only status report most of the hostage families have had since the invasion three months ago.

Although there is no way to verify that the letters are authentic or written free of Iraqi interference, the State Department official said that families were interviewed about about the contents and handwriting in the missives and "everybody pretty much feels the writing is in the style of their loved ones." The official added that "we have not seen any indication of editing."

The State Department forwards the letters to families with a request that they call the department and read back portions.

In one letter, the name of the location where the writer was being held was scratched out in blue pen, said the wife of a hostage who read the letter to a reporter over the telephone.

The letters are filled with emotions: frustration over not knowing when captivity will end; the loneliness of separation from spouses and children, and boredom.

On Sept. 7, Fred Harrington, a Washington state businessman held in Iraq, wrote to his wife: "Darling, days and nights are very boring here. Food is lousy, but we have to put up with it. It is a very uncomfortable life . . . . "

Another hostage wrote a Sept. 13 letter to his wife in New England, describing life in a two-room, air-conditioned portable building, with bathroom and dining room. "We've done a lot of cleaning up but we'll never be able to get it to a sanitation Grade A. . . . The washing water is brackish with a high salt content and it's hard to get the soap to lather . . . the food is okay if you like rice and not a lot of variety . . . ."

He said he has been treated by a doctor for dysentery, has spent time playing cards and is allowed each morning to take a 40-minute walk around the perimeter of the "camp." The armed guards are "generally courteous, some even friendly . . . . The guards eat what we eat."

Since the invasion, the hostages have been the intermittent focus of attention by both Saddam and President Bush. Allowing the letters to leave Iraq, experts said, is Saddam's attempt to refocus attention on the human cost of any U.S. military action.

The hostage issue "cuts both ways," said Laurie Mylroie, an Iraq analyst at Harvard University's Center for Middle East Studies. "Bush tries to use it to signal to Saddam that American lives matter to the American public, to use it in an assertive way," but for Saddam, the hostages "also become an argument for not taking military action."

The letters and phone calls have also provided the State Department with information to use against Saddam.

Yesterday, State Department spokesman Richard Boucher told reporters that hostages who spoke with their families over the weekend reported that "consistent with other reports we have received, many detainees said they were losing weight, that the food was poor, and that with the approach of winter, they were frequently cold." Some hostages "expressed concern that the medication they were using was running out," he said.

Boucher said Saddam "has chosen to play games with innocent human lives. We think that if he's genuinely concerned about allowing husbands and fathers to talk to their wives and children, he should simply release all the hostages and let them come home."

But experts said Saddam would lose important bargaining chips if he were to free all of his captives. For one, he is using the selective release of hostages to try to break the alliance of nations supporting the economic embargo against him; for another, he is able, through the letters and through journalists' interviews with hostages, to dispute Bush's assertions that the captives are being mistreated. Saddam may read these assertions as an attempt by Bush to lay the groundwork for a legitimate reason to strike militarily, the experts said.

"We're having a media war. The Americans say one thing; the Iraqis say another," said Salim Mansoor, whose Iraqi-American Foundation here paid a Iraqi-approved visit to the hostages last month and helped negotiate the release of several American captives. "This is why he's calling them his 'guests.' He says, 'I'm not going to mistreat them, but I'm going to hold them as shields.' He thinks the hostages can deter an attack against his government."