Sen. Ted Cruz opened Thursday night's Republican debate by criticizing President Obama for not mentioning the 10 U.S. sailors detained by Iran in his State of the Union speech this week.

"In that State of the Union, President Obama didn't so much as mention the 10 sailors who had been captured by Iran. President Obama is preparing to send $100 billion or more to Ayatollah Khamenei and I'll tell you it was heartbreaking, but the good news is the next commander in chief is standing on this stage," Cruz said during the debate on Fox Business.

Ten U.S. sailors accidentally sailed into Iranian waters on Tuesday afternoon and were detained by Iran overnight. The Pentagon on Thursday said that it was due to a navigational error.

Following the sailors' capture, Iran released videos of a sailor apologizing for the mistake and sailors on their knees in their patrol boats as they were being detained.

"Many of us picked up our newspapers and we were horrified to see the sight of 10 American sailors on their knees with their hands on their heads," Cruz said.