Beirut, Lebanon ? Lebanese authorities said they halted a bomb attack against the U.S. Embassy on Wednesday, arresting two men outside the compound, one of whom was carrying more than two pounds of explosives.

A Lebanese man in his 30s, identified as Abed Mreish, was seeking to enter the embassy when he was stopped at an army checkpoint about 500 yards from the complex, a senior Lebanese security official said.

A Palestinian taxi driver was arrested as a possible accomplice.

“The device did not explode, nor was anyone harmed,” said State Department spokesman Richard Boucher.

The interception came less than a week after the State Department urged Americans in Lebanon to keep a low profile, vary times and routes of travel and avoid Palestinian refugee camps because of growing tensions and anti-American rhetoric in the Middle East.

Security has been very tight at the U.S. Embassy in Lebanon since the 1980s, when suicide bombers carried out two attacks on embassy buildings. On May 30, the United States reopened its consulate in Beirut, nearly 20 years after its closure during the country’s 1975-90 civil war.

The Lebanese security official, who spoke on condition of anonymity, refused to speculate on the Mreish’s motives, saying army officers were interrogating him.

The Lebanese Army said in a brief statement that the men were attempting to bring a bomb into the embassy compound.

Accounts appeared to vary on who foiled the would-be attack.

The Lebanese security official said it was Lebanese soldiers who stopped Mreish. He said Mreish was carrying more than two pounds of explosives in a small suitcase.

But Boucher said Mreish was stopped by Lebanese working for the U.S. Foreign Service, apparently guards. He also said the Palestinian apparently drove the bombing suspect to the embassy but that it was unclear if he knew about the plot.

A State Department travel warning posted on the U.S. Embassy Web site last Friday did not refer to a specific threat in Lebanon. However, it cited bomb attacks against American fast-food franchises and a British supermarket chain.