(CNN) - On the heels of Hillary Clinton's new campaign ad suggesting Barack Obama is ill-equipped to handle an early-morning foreign policy crisis, the Illinois senator said he thinks his rival for the Democratic presidential nomination is becoming a "little desperate."
"I think she has got a little desperate toward the end of this campaign," Obama told ABC in an interview set to air Monday night. "[She] has been a lot more aggressive in her negative attacks."
Obama's comments come only days after the Clinton campaign released a hard-hitting television spot in Texas that portrays children asleep in their bed while a phone rings in the background. The ad's narrator raises the prospect of a foreign policy crisis and asks, "It’s 3 a.m. and your children are safe and asleep. Who do you want answering the phone?”
Obama's campaign denounced the ad, and the Illinois senator himself quickly hit back, saying Clinton's "red phone moment" came when she voted to authorize the war in Iraq. His campaign also released a rebuttal ad saying the person who answers the phone should be the one who had the "judgment and courage to oppose the Iraq war from the start."
"As I've pointed out, we've actually had a pretty significant moment in the last several years, that called people's judgment into question," Obama said in the ABC interview. "And that was the war in Iraq."
Speaking with reporters Sunday night, Clinton described the ad - and her tougher rhetoric on the trail - as an effort to draw distinctions between herself and Obama.
"I think it's a contrast that needed to be sharpened, because this is a big decision for people," she said. "And I want people to have as much information as possible as they make these decisions. So I think we are helping to get out the differences and raise some issues that are important."
- CNN Ticker Producer Alexander Mooney