Tonight's planned specials on the Persian Gulf crisis are subject to change, network officials say, depending on the "level of engagement." All networks say they are prepared to go to a round-the-clock all-news format if the country is engaged in war.

*CNN: All programming will be Gulf-related from 6 p.m. to midnight tonight. "Crossfire" and "Larry King Live" will deal with the Gulf. Phebe Marr, President Bush's adviser on Iraqi military affairs, will be Mr. King's guest.

*CBS: "48 Hours" will examine the Gulf crisis at 8 p.m. on WBAL-TV (Channel 11). At midnight, CBS will show a one-hour version of "America Tonight" on the Gulf crisis, with Dan Rather in New York, Lesley Stahl and Charles Kuralt.

*ABC has a one-hour version of "Nightline," with Ted Koppel in Jordan, at 11:30 tonight on WJZ-TV (Channel 13).

*NBC has a half-hour special with Tom Brokaw in New York at 11:30 tonight on Channel 2.

*PBS's "MacNeil/Lehrer" at 7 tonight on MPT (Channels 22 and 67) will be devoted to the crisis.