By Kevin Anderson BBC News Online, Washington

Muslims in the United States braced themselves for a fresh backlash and what they see as anti-Islamic bias.

Sniper suspect John Allen Muhammad converted to Islam in the mid-1980s, and Islamic groups are afraid it will touch off threats and attacks similar to those that followed the 11 September attacks.

Muslim groups were quick to condemn the shootings and distance themselves from the sniper.

And they told members of their community to go about their daily activities with increased caution

Prayers

Islamic leaders said that they had been praying that the sniper had no connection to Muslims.

John Allen Muhammad worked as a security man at the Nation of Islam's "Million Man March" in Washington.

The American Muslim community should not be held accountable for the alleged criminal actions of what appear to be troubled and deranged individuals

Nihad Awad, Council on American-Islamic Relations

With the arrest, Muslims now fear a new round of discrimination and intimidation.

"We are concerned that because a suspect in this case has the last name of Muhammad, American Muslims will now face scapegoating and bias," said Nihad Awad, executive director of the Council on American-Islamic Relations (Cair).

He cautioned the media not to engage in speculation about the sniper based on religious stereotypes.

"The American Muslim community should not be held accountable for the alleged criminal actions of what appear to be troubled and deranged individuals," Mr Awad said.

Anti-Muslim discrimination

Cair said it received 1717 reports of harassment, violence and other discriminatory acts in the first six months following the 11 September attacks and 325 reports in the following six months.

It was a 30% increase over the same period before the 11 September attacks.

Some incidents were particularly violent. In the state of Ohio, a man slammed his truck into a mosque near Cleveland.

In August, an 18-year-old man raped a 15-year-old girl in California while making anti-Muslim comments.

Shots have been fired at Muslim community centres in Nevada, Ohio and Texas.

Other centres and schools across the US were vandalised.