The United States is engaged in "urgent" discussions about providing military aid to Tunisia to help that North African country respond to an armed raid into its territory Sunday, the State Department said yesterday.

Although department spokesman Hodding Carter refused to give details of the talks, reliable sources said they are likely to result in the United States airlifting 30 to 40 armored personnel carriers to Tunisia as a show of support.

France disclosed Wednesday that it is sending a naval force toward North Africa in response to appeals for help from Tunisian President Habib Bourguiba.

Tunisian military forces repelled the attack by anti-Bourguiba rebels on the town of Gafsa in south-central Tunisia. Although the latest reports from the region indicated that the rebels apparently came from Algeria, the Tunisian government has charged the radical regime of Muammar Quadiffi in Libya with instigating the attack.

Despite Libyan denials, Tunisia expelled the Libyan ambassador Wednesday night and recalled its ambassador from Tripoli.

Yesterday, Carter refused to say whether the United States knew who was responsible for the attack that Tunisia says resulted in 41 people being killed and 111 wounded.

However, he said the United States, as a longtime friend of Tunisia, was discussing "on an urgent basis" what it could do to help. The talks are understood to have been with Gen. Boubaker Balma, chief of staff of the Tunisian armed forces, who has been in Washington.

U.S. officials later said privately that Tunisia, in addition to a number of longstanding disputes with Libya, has come under increasing fire lately from radical Arab states because of its generally moderate, pro-western positions. Along with Egypt, for example, it has been the most outspoken Arab country in supporting the United States over the American hostages in Iran.

The officials, who said the U.S. aid packages should be made public shortly, said it would include some items other than personnel carriers. The assistance will be "essentially military and on a short-term basis," they said.

In the past, the United States has sold only modest quantities of military equipment to Tunisia.

Carter noted the French movement of warships to the area was a natural response in light of the long ties between France and Tunisia. But he said there are no plans for the United States to take similar action.