A Houston Starbucks reportedly kicked out a group of former Muslim customers Saturday for wearing T-shirts that said, "I'm an Ex-Muslim ask me why?"

The incident was filmed by members of Ex-Muslims of North America (EXMNA), an organization that promotes secular values and fights discrimination against people who leave Islam. The video shows the volunteers being asked to leave a Starbucks inside a Hilton Hotel.

"You're not allowed on the property," a hotel representative is heard saying on camera.

When asked why, the representative responded saying, "Because you're not allowed, you've got shirts right now."

"If you didn't have your shirts, wouldn't start any type of issue, we would have no problem," he added.

The hotel representative insisted that the volunteers were "part of the protest" and could not be in the building. The Islamic Society of North America (ISNA) was holding its 55th annual convention nearby. The EXMNA members were not there to protest the event, but to speak with attendees about tolerance and ex-Muslim rights.

"We're not part of the protests," a volunteer said. The Hilton representative replied saying, "It doesn't matter."

He threatened the ex-Muslims with arrest if they entered the Starbucks again.

EXMNA later released a statement explaining what happened before the cameras began rolling.

"The EXMNA volunteers were taking a coffee break at the Starbucks after a day of handing out flyers and speaking with and interviewing attendees at the Islamic Society of North America (ISNA)'s annual conference," EXMNA explained in a press release. "Without warning, they were informed by staff that they must leave the establishment."

The volunteers were taken aback by the demands.

"I was surprised. I was simply drinking my iced coffee and scrolling through my phone, and they told me I needed to leave, so I asked why," said Lina, an ex-Muslim Syrian woman who had traveled to the conference on behalf of EXMNA. "I was told that they are not allowing protestors at the property. I assured the woman that I was not a protestor. She then asked me if I was part of the event or a guest at the hotel. I was neither. I was then told that even though I was a paying customer, I was not allowed to be on the premises as it was reserved for guests and event members for the weekend and that they will not be allowing anyone else on their private property. However, I noticed the Starbucks was still open to the public and I didn't see anyone else being asked to leave."

President of Ex-Muslims of North America Muhammad Syed believes this is the type of discrimination his organization works to expose and stop.

"The treatment was unjust and especially cruel considering the plight of ex-Muslims. We are killed and abused all over the world for our disbelief. It is unconscionable that companies like Starbucks and Hilton acquiesce to conservative religious sensibilities," he said in a statement.

Armin Navabi is an ex-Muslim atheist who also attended the conference. He was surprised that most of the backlash didn't come from the Muslims he talked to.

"Our goal was to see how tolerant Muslims can be, to our delight, we found many Muslims were tolerant," he stated. "On the other hand, we found that many Westerners were intolerant. It seems that ‘saviors’ of Muslims are more sensitive about anything that could potentially offend Muslims than Muslims are themselves."

CBN News reached out to both EXMNA and the Hilton Hotel. We did not receive a response at the time of publishing.