Those fires follow "the worst year on record for incidents in which mosques were targets of bias," according to the Council of American-Islamic Relations.
CAIR documented 139 incidents of "damage/destruction/vandalism" at mosques last year -- the most since record-keeping began in 2009. It does not track fires separately.
"Islamophobic bias continues its trend toward increasing violence," said Corey Saylor, director of CAIR's Department to Monitor and Combat Islamophobia.
The wave of hostility comes as President Donald Trump campaigned on -- then enacted -- a temporary ban on travelers from Muslim-majority countries entering the United States. He is said to be drafting a new version
after the first was struck down in court.
Here's a look at the mosque fires so far this year:
January 7: Austin, Texas
The Islamic Center of Lake Travis' new mosque hadn't even been completed yet when it mysteriously caught fire.
Leaders said the center had suffered vandalism and graffiti in the past, but this fire was devastating.
"You can imagine the emotions that we experienced upon seeing all our hard work, heartfelt efforts and dedication literally go up in flames," the Islamic center posted in a statement
The damage, estimated at $370,000, was considered a complete loss, the Travis County Fire Marshal's Office said.
The cause of the fire remains under investigation.
January 14: Bellevue, Washington
A fire that torched the Islamic Center of Eastside near Seattle was an act of arson, Bellevue Police Chief Steve Mylett said.
No one was inside the mosque at the time of the blaze, which firefighters said shot 40-foot flames into the sky
The police chief said Isaac Wayne Wilson has been charged with felony malicious mischief and was being investigated for arson. Police found the suspect lying on the ground near the back of the building, CNN affiliate KCPQ
The mosque is asking for donations to rebuild
. In recent months, backers of the fund-raising campaign said, "This center and a neighboring Islamic center have seen numerous acts of vandalism."
January 27: Victoria, Texas
The fire that destroyed the Victoria Islamic Center mosque was intentionally set, the Houston office of the Bureau of Alcohol, Firearms, Tobacco and Explosives said.
The ATF, CrimeStoppers and the mosque are offering a combined $30,000 reward for information leading to the arrest and indictment of whoever set the mosque on fire.
While members of the mosque grappled with their loss, leaders of a local Jewish congregation stepped in to help -- and gave them the keys to their synagogue
so they could continue to worship.
February 24: Thonotosassa, Florida
A fire that damaged the Islamic Society of New Tampa has been ruled arson, Hillsborough County fire investigators said.
Authorities have not ruled whether the fire was a hate crime, but Tampa Mayor Bob Buckhorn said the attack "is no different than the wave of anti-Semitic attacks on Jewish community centers and synagogue and bomb threats
that have been called in all across the country, including in Tampa over the recent months."