American Describes Surviving Suspected Terrorist Attack at Berlin Christmas Market

— -- Shandana Durrani, a U.S. woman who was visiting the Berlin Christmas market Monday when a truck plowed through, said she believes a friend’s text message saved her life.

"I was on my way out of the market after doing a little bit of shopping," Durrani said today from Berlin on "Good Morning America." "I stopped to respond to a text message that I had gotten from a friend and I think that’s basically what saved me from being hit because as I looked up, this truck was barreling through the market and through the stalls and through the crowd coming almost at me."

At least 12 people were killed and 48 others injured after the truck drove into a crowded Christmas market in a public square in Berlin.

The truck was driven into the crowd in what investigators believe was a terrorist attack, Berlin Police tweeted early today.

Durrani, a travel and lifestyle journalist who moved to Berlin recently for work, did not immediately think the destruction was the result of a terrorist attack.

"I just thought that somebody had lost control of a truck and, you know, hit the curb and went over the curb," she said. "It happened so fast. It felt like slow-motion but I think it was like 10, 15 seconds of it. I didn’t immediately think terror attack."

Durrani added that as a Muslim-American, the thought that the Berlin incident could be another terror attack "just makes me nauseous."

"I try not to think about that, try not to think that could happen again and, unfortunately, it looks like it did," she said.

Flags flew at half-staff across Germany today as the country mourned the victims. Christmas markets in Berlin closed for the day and the attorney general announced the beginnings of a criminal investigation.

"This is a difficult day. I am, like millions of people during these hours, horrified and shocked by what happened at the Breitscheidplatz in Berlin," German Chancellor Angela Merkel said in a brief statement today.

"We must assume that it was a terrorist attack," Merkel added.

Durrani, a Detroit native, said she hid with a few other people behind a stall in the Christmas market until they thought "the coast was clear." She said they walked out of the stall to "stunned" and "screaming" people and bodies on the ground.

"I have to say kudos to the Berlin police and fire department and EMTs," Durrani said. "They were there very quickly. They cordoned off the scene. They got rid of all the bystanders and, you know, separated them from the people who really needed the help who were the victims."

ABC News' Matthew Stone, J.J. Gallagher and Michael Edison Hayden contributed to this report.