By AHMED AL-HAJ and SALAH NASRAWI

SAN’A, Yemen — Arab diplomats say Saudi Arabia has launched a large military incursion across the border into northern Yemen, aimed at ending a Shiite rebellion inside its troubled southern neighbor.

Two diplomats, speaking on condition of anonymity Thursday, say Saudi Tornado and F-15 warplanes have bombarded targets inside Yemen since Wednesday afternoon, inflicting significant casualties on the Yemeni rebels. The diplomats spoke on condition of anonymity because they are not allowed to speak to the media.

The Arab diplomats say army units and special forces have been sent to northern Yemen, and that several Saudi towns on the border have been evacuated.

Neither Saudi Arabia nor Yemen have confirmed the offensive. But a rebel spokesman told The Associated Press that Saudi warplanes and artillery hit several areas Thursday.