HEBRON, West Bank -- Dozens of Israeli tanks and armored vehicles entered the West Bank city of Hebron early today.

The incursion came from the north, south and west, and was accompanied by attack helicopters, firing machine guns from the air.

A Palestinian member of one the security forces was killed and at least 15 people were wounded by Israeli gunfire, mostly from the helicopters, Palestinians said.

Israeli military sources confirmed that a military operation was under way, but would give no further details. Israel Radio said the object of the incursion was to arrest militants, not to occupy the city, but residents said it was the largest military operation in Hebron in months.

It was not clear if the incursion marked a full invasion of the city, the only main West Bank population center that escaped Israel's large-scale military push that began March 29. Israeli troops also bypassed the desert oasis town of Jericho during their sweep.

Moving in force in response to a series of deadly Palestinian suicide bombing attacks, Israeli troops took control of the other main cities and fought house-to-house battles in the Jenin refugee camp and the old city of Nablus. The fighting ended two weeks ago, and Israeli forces withdrew from most of the towns.

In today's incursion, Israeli troops moved about 1 1/2 miles into Hebron and appeared to be concentrating on two specific areas, indicating the object was to make arrests.