Updated

The U.S. Embassy in Saudi Arabia has warned Americans that new information indicates "known terror operatives" are studying outdoor areas in the kingdom frequented by Westerners.

The message, posted on the embassy's Web site Monday, urged U.S. citizens to be vigilant, but said it was unknown if the new intelligence involved plans for possible terrorist attacks.

"Recent information has come to the embassy's attention that known terrorist operatives in Saudi Arabia have reference material identifying popular trails and campsites in Saudi Arabia often used by westerners," the message read.

The message did not identify the source of the information. Saudi officials could not immediately be reached for comment.

A State Department announcement last week warned of anti-American sentiment in the region and said credible information indicates that terrorist groups may be planning attacks against U.S. targets in the Middle East.

Last week, the U.S. Embassy in Yemen (search) also announced new information indicating that western interests in Yemen may be targets.

Saudi Arabia was recently praised by senior U.S. officials for increasing cooperation in the fight against terrorism.

At least one person wanted by the FBI is also on the most wanted list in the kingdom for possible links to the May 12 bombings in Riyadh (search) that killed 26 people along with the nine bombers.