Security is being increased in key countries around the world today as an international watch for more terrorist attacks is underway. The U.S. embassy in Riyadh said American consulates in the kingdom - and the embassy itself - would be closed beginning Wednesday due to information that a terrorist attack may be imminent.

The heightened concerns come after another apparent terrorist attack in Turkey. At the same time investigations are ongoing into last week?s other deadly terrorist bombings in Morocco and Saudi Arabia. VOA-TV?s Chris Simkins has more.

The latest bombing was at a cafe in Ankara located in one of the busiest sections of the capital. Turkish police say the apparent suicide attacker, a woman, was killed and another person was injured.

There was no immediate claim of responsibility. In the past, Turkey's extreme-leftist groups and separatist Kurdish rebels have carried out suicide attacks on civilian targets.

The Turkey bombing is the latest in a string of terrorist attacks that have left a trail of death and destruction in Saudi Arabia and Morocco. So far more than 75 people have died and hundreds of others have been injured in the wave of attacks.

In Casablanca, Moroccan authorities have rounded up at least 30 suspects in connection with a series of bombings. Police say they are interrogating two men in connecting with Friday?s attack. Intelligence officials tell the American television network ABC News that a number of the attackers, who were Moroccans, trained in al-Qaida training camps in Afghanistan.

Morocco?s Foreign Minister:

?We do not know precisely who is behind it, but the similarities of the acts, the nature of the terrorist acts leads us to believe that there is a foreign hand behind it.?

While there have been no direct al-Qaida links to the Moroccan bombings, U.S. intelligence believes its leadership including the terror network?s new military commander is working in Iran. Counter-terrorism analyst Richard Clarke says al-Qaida may be planning more attacks.

?It has tens of thousands of trained operatives that were trained in the camps in Afghanistan who are still at large. So although we?ve done a lot of damage to al-Qaida, it?s still a potent force.?

In Riyadh, Saudi Arabia, investigators pour over forensic evidence from attacks last week when terrorists exploded car bombs at several residential compounds where many foreigners lived. Thirty-four people, including eight Americans died. The Saudi government blames al-Qaida.

Saudi ambassador to the United States Prince Bandar bin Sultan says he fears there could be another big terrorist attack on either his country or in America. In the United States the color-coded terror alert system was raised to ?Orange? for high. The FBI is warning law enforcement agencies around the country to be on alert for a possible attack.

U.S. Congressman Porter Goss is Chairman of the Intelligence Committee:

?The statistical odds are that we (The United States) are going to get hit domestically and that?s just a fact that we shouldn?t sugarcoat.?

Despite, the renewed concerns about terrorism in the United States, the head of department of Homeland Security told lawmakers the nation is safer than it was 20 months ago. But Tom Ridge said that law enforcement agencies must still remain vigilant about confronting threats of terrorism.