| ISMAILIA, Egypt
ISMAILIA, Egypt Two Iranian naval ships passed through Egypt's Suez Canal into the Mediterranean on Tuesday heading for Syria, a source at the canal authority said, a move certain to anger Israel.
Iran appears to be testing the state of affairs in the Middle East after the fall of Egyptian President Hosni Mubarak. A longstanding peace treaty with Egypt is crucial to Israel's regional security.
The ships entered the canal at 5.45 a.m. (10:45 p.m. EST on Monday) on Tuesday and passed into the Mediterranean at 3.30 p.m. (8:30 a.m. EST), the Suez Canal Authority source told Reuters. "Their return is expected to be on March 3," the source said.
The Suez Canal cuts through Egypt and allows shipping to pass from the Middle East to Europe and vice versa without going around the southern tip of Africa.
The canal's northern mouth, Port Said, is around 100 km (60 miles) from Israel, but the ships' route would take them into the Mediterranean along Gaza and the Israeli coast. The vessels, the first Iranian navy ships to enter the canal since Iran's 1979 Islamic revolution, are a frigate and a supply ship.
Israel is anxious about political upheaval in Egypt and other Arab states aligned with its ally the United States and its Prime Minister Benjamin Netanyahu had previously said he would take a "grave view" of the passage of Iranian naval ships.
Israeli officials declined comment. Israeli media have quoted unnamed navy officials as saying the Iranian vessels would be tracked, but not confronted.
Polls in Egypt suggest most of main political forces will be less compliant with Israel and its ally the United States, although no group has called for the abrogation of the Israeli-Egyptian peace treaty.
A recently completed Israeli war game, the first since Mubarak quit Egypt's presidency, concluded it would boost military preparations but try to avoid confrontation unless it sees a greater threat from Iran.
Separately, Israel announced on Tuesday that its Arrow II missile shield had aced its latest live trial, shooting down a target missile off a U.S. military base on the California coast.
Israeli defense official Arieh Herzog said the test marked Arrow's upgrade "to contend with new and additional threats" in the Middle East.
"Arrow can intercept all of the weapons arrayed against it in the region, including those that are liable to come from Iran," Herzog told reporters.
Egypt's ruling military council, facing its first diplomatic headache since taking power on February 11, approved the two vessels' passage through the canal, a vital global trading route and major source of revenue for the Egyptian authorities.
The decision was difficult for Egypt's interim government. Cairo is an ally of the United States while its relations with Iran have been strained for more than three decades.
Analysts say Iran sees itself benefiting from the upheaval across the Middle East. Dislodgement and weakening of leaders sympathetic to the United States are likely to embolden Tehran, and lessen the chances of it making concessions on its nuclear program. Iran denies it intends to build atomic weapons.
(Additional reporting by Dan Williams in Jerusalem; Writing by Edmund Blair, Maria Golovnina and Sarah Mikhail; Editing by Louise Ireland and Daniel Magnowski)