Justin Bieber responds to pot-smoking photos

What does Justin Bieber have to say for himself after photographs of him smoking what looks like marijuana were published on the Internet?

"Everyday growing and learning. Trying to be better. U get knocked down, u get up," the 18-year-old pop star wrote on Twitter "I see all of u. I hear all of u. I never want to let any of you down. I love u."

Though the pop star didn't address the pictures directly, he did reference "new challenges" and "new doubts," US Weekly reported.

The photographs were taken on Jan. 2 inside a hotel room in Newport Beach, Calif. and were published by TMZ. According to Glamour and Us Weekly, Bieber had security present at the party, and his team is investigating how the photographs were leaked.