ORLANDO – Fearing retaliation after Orlando shooting, Florida mosques have stepped up security measures during Friday prayer after mosques received threats and angry messages in telephone calls and on social media.

“We are tremendously threatened,” Muhammad Musri, the imam of Masjid Al-Rahman, told The Wall Street Journal on Sunday, June 19.

Fear increased after Omar Mateen, a US citizen, killed 49 people at a packed gay nightclub in Orlando, Florida on Sunday and wounded 53 others before being killed by police in the worst mass shooting in US history.

Since the Sunday shooting, the mosque has received letters and emails ranging from critical to menacing.

“Some of the messages were, ‘We know where you are, we know your location … we will come at the right time,’ ” Musri said.

The fear was spread across different mosques throughout central Florida, home to tens of thousands of Muslims.

According to the state chapter of the Council of American-Islamic Relations, mosques across Florida have received threats and angry messages in telephone calls and on social media

The Federal Bureau of Investigation and local officials publicly warned against threats or violence toward Muslims and their property.

Earlier this week, CAIR urged Muslim community leaders to consider instituting additional security measures in the wake of the Orlando massacre and a number of recent hate incidents targeting Muslims and Islamic houses of worship.

“Because of the recent tragic attack in Orlando and the anti-Muslim political climate, we urge local community leaders to seek increased police patrols in the areas surrounding mosques and Islamic institutions nationwide,” said CAIR National Executive Director Nihad Awad.

“The targeting of one minority group by hate should not result in the targeting of another.”

In response to incidents targeting Muslims and their institutions, CAIR printed additional copies of its booklet, “Best Practices for Mosque and Community Safety.”