The American embassy in Sofia opened for business on Wednesday morning, less than 24 hours after a series of devastating terrorist attacks temporarily shut down the U.S. government, and caused shock and concern worldwide.

"There is no sensed need to close the embassy for our security postures. If we feel there is a need, we will do so," a U.S. embassy spokesman said on Wednesday. Business hours have not changed and consular services are working normally.

A statement released by the embassy that afternoon said it had increased its own security measures and had requested Bulgarian authorities to provide additional protection around its facilities. "Even though we are unaware of any threat against American citizens or U.S. facilities in Bulgaria, we urge all American citizens here to exercise an extra level of security consciousness," it said.

The embassy closed for 24 hours just over two weeks ago to do a thorough check of its security procedures. The U.S. embassy spokesman said that check was in response to a general State Department warning in June, and was in no way connected to this week's events. The only warning was the general sense that some terrorist activity was brewing and security was increased as a result.

The spokesperson said that while there was tremendous shock and concern within the embassy, it has received a tremendous amount of support. On Tuesday night and Wednesday, officials received a flood of faxes and emails from many different facets of Bulgarian society with condolences and offers to donate blood.

American expatriates living in Bulgaria can call the embassy switchboard 24-hours a day for advice if they are concerned about this week's events or visit its website at www.usembassy.bg.

Security has similarly been increased at all U.S. institutions operating in Bulgaria, including the offices of USAID and the U.S. Peace Corps.

Petya Stoeva, media and public relations co-ordinator, at the American University in Bulgaria, said the situation is similar in Blagoevgrad. "There is increased security around the main university building and dormitories but there is no needless panic among U.S. citizens here. Classes have not been stopped and the university functions as usual." She added the U.S. and Bulgarian flags have been lowered as a sign of mourning.

Christina Vassileva, public relations co-ordinator at the American College in Sofia, said there have not been any problems there. "The atmosphere in the college is calm and normal. We are situated near the Police Academy in Simeonovo, so there is high level of security anyway."

The British embassy has been put on high alert but is operating normally. Christine Winterburn, embassy press secretary, said that terrorism will not disrupt the day-to-day running of the embassy.

At the Israeli embassy however, it was a different story. On Wednesday consular services were not operating. "Who has to be here is here. Who doesn't have to be here is not here. I am here," Israel ambassador to Sofia Emanuel Zisman told the Bulgarian News Agency on Wednesday.

The Levski-Chelsea UEFA Cup football match, which was scheduled to be played yesterday in London, was postponed a week as a result of the events in the U.S.