TEL AVIV, JAN. 30 -- Following two consecutive nights of rocket attacks into Israeli-controlled territory in southern Lebanon and an attempted border incursion from Jordan, Israeli military and government officials said today they believe the Palestine Liberation Organization has begun operations against Israel on behalf of Iraq.

The officials said Iraqi President Saddam Hussein, frustrated by the relative ineffectiveness of his missile attacks on Israeli civilian population centers and his failure to draw Israel into the Persian Gulf War, has instructed PLO Chairman Yasser Arafat to order his mainstream Fatah forces to harass Israel's frontiers in hopes of increasing pressure on the Israeli government to enter the gulf conflict.

"Saddam Hussein has started to open new fronts. His missile attacks from the western {Iraq} desert didn't achieve the desired results. Now he's getting desperate and he's playing the PLO card," said Col. Raanan Gissen, army command spokesman.

Gissen added, "We may be seeing an intensification of efforts to penetrate our borders and subject the northern border to Katyusha {rocket} attacks. I'd anticipate they will do more, and we will be ready for them."

Israeli military officials said Fatah forces, in concert with Palestinian and Lebanese militias operating in southeastern Lebanon, fired dozens of Katyusha rockets toward the Israeli border Monday and Tuesday nights. None of the rockets landed in Israel, and the Israelis retaliated with naval and artillery barrages.

Government spokesman Yossi Olmert said, "I think they are trying to open a new front in support of Iraq. But Lebanon is not Iraq, and there is no doctrine of not responding in that direction." He was referring to Israel's policy of military restraint in the face of Iraq's attempts to provoke it into entering the war, a step that could alienate the Arabs in the multinational coalition against Iraq.

The commander of Fatah forces in Lebanon, Col. Zeid Wehbe, was reported to have said that rocket attacks aimed at northern Israel had been launched on the orders of Arafat in Tunis. News agencies quoted Wehbe as telling reporters in Sidon, "We now have an open-war border with Israel. This is Saddam Hussein's northern front."

However, the PLO command in Tunis, was reported to have denied that Arafat had given any orders to fire on Israel, and said Wehbe had been reprimanded.

Israeli officials dismissed the denial, saying he cannot afford to openly associate himself with Iraq's war effort and further alienate the moderate Arab states that have been his principal sources of financial support.

Gissen said Arafat "understands well that nothing good will come of his being so closely associated with Saddam's war. On the other hand, he can't ignore the pressure from the PLO rank and file, which is clearly in support of Iraq. The best he can do is quietly consent to terror attacks against us."

Monday night's Katyusha barrage was the heaviest against Israel's northern border in five years, and appeared to be the first Fatah attack directed at Israel since the PLO leader renounced terrorism in December 1988.

Gissen said the army command had "hard" intelligence that the radical, pro-Iranian Hezbollah militia operating in southeastern Lebanon, which frequently has clashed with Palestinian forces and Lebanese militias in the region, had assisted in setting up the multiple-rocket launchers aimed at Israel's border.

The rockets fell short and landed in the 440 square-mile buffer zone in southern Lebanon that is controlled by Israel's surrogate force, the South Lebanon Army. Some of the rockets exploded near the border security fence separating Lebanon and Israel, but caused no casualties, the Israeli military command said.

Israeli forces responded by firing on Fatah strongholds in the Rashadiyeh refugee camp, near Sidon, and two villages in the Syrian-policed Bekaa Valley from offshore gunboats and from artillery batteries in the security zone, Army spokesmen said.

Early today, the army command said, an Israeli patrol in the Jordan Valley encountered two armed men who had crossed the border near the Adam Bridge, killing one of them in an exchange of fire and pursuing the other until he crossed back into Jordan. A military spokesman said the infiltrator who was killed was wearing a Jordanian army uniform and carrying an M-16 rifle.