President Bush declined Thursday to criticize Israel's tactics in its continuing offensive against Hezbollah guerrillas in southern Lebanon, and gave a sharp condemnation of Iran's role in the bloody fighting.

"Hezbollah attacked Israel. I know Hezbollah is connected to Iran," Bush said tersely at the end of Oval Office meetings with Romanian President Traian Basescu. "Now is the time for the world to confront this danger," Bush said.

The president was responding to statements from top Israeli officials that fighting could continue for several weeks more. Israeli Justice Minister Haim Ramon said world leaders, in failing to call for an immediate cease-fire during a Rome summit, gave Israel a green light to push harder to wipe out Hezbollah.

Click here to visit FOXNews.com's Mideast center.

Bush said he hoped to see the violence end "as quickly as possible" and repeated his call for Israel to try to limit the impact on civilians. But he suggested that the Israeli campaign has his support for as long as it takes to eliminate Hezbollah's influence in Lebanon and its ability to attack neighbor Israel.

"Now is the time to address the root cause of the problem and the root cause of the problem is terrorist groups trying to stop the advance of democracy," he said. "Our objective is to make sure that those who use terrorist tactics are not rewarded."

The Israeli offensive, which began after Hezbollah crossed the border and captured two Israeli soldiers, continued Thursday as Bush spoke. Israeli jets pounded suspected Hezbollah positions across Lebanon on Thursday, and guerrilla rockets continued to hit northern Israel.

In response, the Al Qaeda terrorist network threatened new attacks, its first comment on fighting now in its third week. The videotape by Usama bin Laden deputy Ayman al-Zawahri also was the first sign that Al Qaeda aimed to exploit Israel's two-pronged offensive — against Hezbollah in Lebanon and Hamas-linked militants in Gaza — to rally Islamic militants.

"I'm not surprised people who use terrorist tactics would start speaking out," the president said. "Here's a fellow who is in a remote region of the world putting out statements basically encouraging people to use terrorist tactics to kill innocent people to achieve their political objectives. And the United States of America stands strong against Mr. Zawahri and his types."

Click here to visit FOXNews.com's Mideast center.