Each year on Eid al-Fitr, the end of the Ramadan month of fasting, 8,000 to 10,000 Muslims stream into the Muslim Community Center in Silver Spring, Md., in shifts for special Eid services, followed by food, singing, dancing and henna decorating to celebrate one of Islam’s most festive holidays.

The religious services are on for this year. But not the rest.

“No celebrations, no festivities,” said Rashid Makhdoom, who is on the center’s board of directors. By uncomfortable coincidence, the holiday falls this year around Sept. 11 – for the first time since the 2001 terrorist attacks.

Eid, like other Muslim events, is calculated on a lunar calendar and occurs slightly earlier each year. This week, depending on when in August one started fasting, it is either on the 9th, 10th, or 11th.

“Particularly, people are taking care not to do any celebrations on the day of 9/11, because it is a day of tragedy and we have to be sensitive,” Makhdoom said. “That’s the mood of the Muslims, generally very subdued.”

U.S. mosques have loudly condemned terrorism, and many services this year will commemorate the victims of the Sept. 11 attacks, including, they point out, Muslims. But many say they are rethinking more festive activities in the wake of what has been a tense summer for Muslims in the United States.

A proposal to build an Islamic center near the site of the World Trade Center in New York has provoked a swell of anti-Muslim sentiment; protesters have targeted mosques in other states; a Muslim cabdriver was stabbed; and a Florida church has said it will burn Qurans on Sept. 11.