Mail is taking longer to reach troops in the Persian Gulf than it did during the pre-Christmas mail crunch and letters coming out of the region are also facing similar delays, Pentagon officials said yesterday.

Letters and parcels are taking an average of 13 to 17 days to reach service personnel in Saudi Arabia, officials said. That's up from a pre-Christmas average of 10 to 12 days and well above the 7-to-10-day average in September and October just after the first U.S. troops deployed to the region.

The reason for the added delay is quite simple, according to Maj. Mark Rader, a spokesman for the Military Postal Service Agency. "It's harder to hit a moving target," he said.

With the start of hostilities, a large number of Army and Marine Corps units began moving toward the border with Kuwait, making it more difficult for the 195 Army and Fleet Post Offices in the gulf area to locate military personnel. "When you are talking about a country the size of Saudi Arabia" the problems can be considerable, Rader said.

Testifying before the Senate Armed Services Committee Thursday, Defense Secretary Richard B. Cheney and Gen. Colin L. Powell, chairman of the Joint Chiefs of Staff, acknowledged they were aware of the problem. "There is nothing more important" than getting the mail delivered, said Powell.

"We are doing everything we can to shorten the time back down because Americans want to hear from their GIs and GIs want to hear from their families and other Americans," Powell said. He expressed confidence that the delays will decrease once the condition of the region "stabilizes a little."

Mail service remains a high priority for Gen. H. Norman Schwarzkopf, the commander of U.S. forces there, Powell said. "And it is something that Gen. Schwarzkopf and I talk about regularly," Powell said. "He's hard at work on it."

Rader said yesterday that part of the problem is that combat supplies must have priority for transportation and the result is that the mail service been given "less space for more volume."

He said the same factors that were delaying mail headed for the troops were also delaying mail leaving Saudi Arabia. In addition, the mail leaving the country is undergoing security screening, which may add another day's delay, Rader said.

Last month the military appealed to Americans not to send parcels to the region, citing the difficulty of transporting packages to combat troops. Mail volume has continued well above the level of the Vietnam War, surprising postal and military officials.

"One of the problems we have had, frankly, is the outpouring of mail that has come not only from the families of servicemen and women over there, but just from the average American to any soldier," Powell said. "That's great and we want to continue that."