Iran successfully tested a medium-range missile Wednesday, a senior administration official said. The weapon, with a range of about 800 miles, is capable of hitting Israel and Saudi Arabia, altering the political and military balance of power in the Middle East.

"This weapon would allow Iran to strike all of Israel, all of Saudi Arabia, most of Turkey and a tip of Russia," said the senior administration official, who spoke on condition of anonymity.Other officials said a U.S. spy satellite had detected the launch Wednesday morning and that intelligence analysts were still poring over data about the missile, which they believe Iran bought from North Korea. The officials are certain that Iran successfully tested the medium-range missile but could not provide information on the location of the launch site or the impact area except to say both were inside Iran's borders.

A former intelligence official familiar with the spread of weapons of mass destruction said: "The major reaction to this is going to be from Israel, and we have to worry what action the Israelis will take because the Israelis clearly view the Iranians as their main threat in the Middle East." Israel is the only nuclear power in the region, and its missiles are believed capable of striking any nation in the Middle East.

In Jerusalem on Thursday, Israel's defense minister said he was concerned about the press reports of the test but said it did not pose an immediate threat to Israel. Defense Minister Yitzhak Mordechai said he did not believe the missile could reach Israel but said this is a "very serious matter."

Other Israeli officials said they did not have independent confirmation of the Iranian test.

Government spokesman Moshe Fogel said Iran's neighbors should also be worried about the Iranian missile program.

"The potential threat to Iraq, Saudi Arabia, the Gulf States and Western interests, particularly those of the United States, is as great as the threat to Israel, if not greater," Fogel told The Associated Press.

Present and former intelligence officials said the missile came from North Korea, which has vowed to continue selling its weapons to any nation that can provide that cash-starved nation with hard currency. The official North Korean news agency issued a statement last month saying that "our missile export is aimed at obtaining foreign money we need at present."

Iran has long sought to launch a medium-range missile and has bought technology from Russia and China as well as North Korea. Tehran's goal, a senior administration official said, was not to strike its enemies but to be viewed as a political and military force to be reckoned with in the Middle East.

Iran is working on developing a nuclear warhead but is believed to be years away from building and testing such a weapon. But the United States is not certain of the size or sophistication of its programs to develop weapons of mass destruction.

"It is a source of concern to us that they are pursuing a program of this nature," presidential spokesman Mike McCurry said Thursday. "We actively monitor (Iran's) military capacity and things like their missile technology," he said.

McCurry disputed assertions that the test had changed the balance of power in the region. "One single missile test does not change balance of power," he said. "What you learn about is direction and intent of programs."