U.S. President George W. Bush paid a visit to the Egyptian embassy in Washington on Monday and declared those who attacked the resort town of Sharm el-Sheikh, have "no heart and no conscience."
"The people who struck at Sharm el-Sheikh killed Muslims, innocent mothers and dads, people who were just trying to make a living," said Bush after signing a book of condolence.
The attacks in London and Egypt have led to increased security in many parts of the U.S.
New York is searching subway passengers. Washington's Metro is also wrapped in tighter security.
Meanwhile, America's Muslim leaders are trying to cool things down.
"The fact of the matter is we know of no sleeper cells, we don't know of that phenomenon to exist in our community," said Esam Omeish, president of the Muslim-American Society. He joined other Islamic leaders in Washington as they launched another campaign aimed at calming public fears.
This one - called Faith Over Fear and Justice for All - is the latest in a long string of attempts by moderate Muslim leaders to condemn terrorism.
"You are a scourge upon the very tenets of Islam and you will find no comfort in our community," said Imam Mahdi Bray.
While the Sept. 11 attackers were all foreigners, it is homegrown militants who have struck in Britain. If the same thing happens in the U.S., Islamic leaders fear violent reprisals.
American Muslims are generally considered to be far less radical than their British and European cousins. But Bray warns that what is now almost four years worth of aggressive penetration of Muslim neighbourhoods by FBI agents and informers may be breeding new militants.
"Rather than spending all of their energies in terms of recruiting spies and snitches they should spend more time and energy engaging the authentic Muslim leadership. That's an important aspect of fighting terrorism. But it's a two-way street," said Bray.