BEIRUT, SEPT. 14 -- Hassan Sabra, the editor in chief of Ash-Shiraa, the Lebanese weekly that exposed U.S. arms sales to Iran last November, was seriously wounded in an apparent assassination attempt here this morning.

Two gunmen on a motorcycle approached Sabra's chauffeured car while it was blocked in traffic, according to police and witnesses, and one of them shot through the window. Sabra was wounded in the neck, head and shoulder. His daughter Nisrine, 8, was slightly wounded.

Authorities had no immediate indication who was responsible for the attack. Sabra's driver said he fired at the two men as they drove off.

Sabra was taken to the American University Hospital, where the bullets were removed. Doctors later said he was out of the critical stage.

The 44-year-old editor received international attention for his disclosure last year of Iranian-American contacts and arms sales aimed at gaining freedom for U.S. hostages held in Lebanon.

His publication often carries brief items about the foreign hostages and purported underground deals for their release. After the Iran-contra scandal made world headlines, Sabra sought to keep Ash-Shiraa in the news by making it available to international journalists ahead of local public distribution.

Today's apparent assassination attempt was the first against Sabra, although he has reported several warnings and kidnap threats. He has openly supported the radical Iranian wing of Ayatollah Hussein Ali Montazeri, the designated successor to Ayatollah Ruhollah Khomeini.

Sabra's publication is noted for its detailed coverage of the power struggle in post-revolutionary Iran as well as the internal political situation in Lebanon.

Although he is a Shiite Moslem, Sabra is a member of the Socialist Arab Union, which is pro-Libyan. Few Lebanese Shiites have been politically friendly toward Libya since 1978, when Lebanon's Shiite leader, Imam Musa Sadr, disappeared while on a visit to Libya.

A special section of Ash-Shiraa specializes in Egyptian groups opposed to the regime of President Hosni Mubarak. Sabra also has criticized Palestine Liberation Organization Chairman Yasser Arafat, Shiite Amal leader Nabih Berri, and Druze chieftain Walid Jumblatt, as well as leftist Lebanese parties.

Last February, on the eve of the deployment of Syrian troops in West Beirut, Sabra lashed out at the rival militias governing the Moslem half of the Lebanese capital. He was one of the first Lebanese journalists to take a strong interest in the Iranian revolution and flew into Tehran on the same plane as Khomeini when he returned home from exile in 1979, after the shah was dethroned.

Sabra is thought by many here to have the protection and support of Syria. He has visited Damascus frequently in recent months.