Richard Dawkins draws criticism for 'clock boy' Ahmed Mohamed tweets

London (CNN) Eminent British scientist Richard Dawkins has drawn criticism on social media for what some say is an unfair comparison between Ahmed Mohamed, the Texas teenager whose school project was mistaken for a bomb, and a young ISIS killer.

But Dawkins says he was merely drawing a parallel between their ages.

"HORRIFIED anyone thinks I could POSSIBLY liken Ahmed to a killer," Dawkins said in a tweet Wednesday. "My ONLY point of comparison was their AGES: kids not immune to criticism."

Dawkins, a leading voice in the atheist movement, was reacting to news that the Mohamed family was demanding $15 million in damages and an apology from city and school officials in Irving, Texas, over their treatment of the teen.

In September, the 14-year-old, who is Muslim, was detained, questioned and hauled off in handcuffsafter bringing a handmade clock to school, which a teacher thought could have been a bomb.

"Don't call him 'clock boy' since he never made a clock. Hoax Boy, having hoaxed his way into the White House, now wants $15M in addition!" Dawkins tweeted Tuesday.

The evolutionary biologist has been vocal in his belief that the case -- which made Ahmed a cause célèbre, prompted the hashtag #IStandWithAhmed to trend, and led to a personal invitation to the White House from President Barack Obama -- was a "hoax."

He has repeatedly insisted that Ahmed did not make a clock but rather "took a clock out of its case and put it in a box," and has questioned the teen's motives in doing so.

'Picking on a kid'

When Twitter users chided the 74-year-old scientist for "picking on a kid," he responded by tweeting a link to a news story about a child ISIS killer.

"'But he's only a kid.' Yes, a 'kid' old enough to sue for $15M those whom he hoaxed. And how old is this 'kid'?" tweeted Dawkins, linking to a story about a young ISIS killer beheading a victim.

Dawkins responded by tweeting that two individuals' "young AGES are being compared, nothing else," and that his point was that "simply that being a 'kid' doesn't protect you from criticism."

He later mused that perhaps a comparison to the killers of James Bulger, a 2-year-old British boywho was abducted, tortured and murdered by two 10-year-olds in 1993, "would have been a better example."

The response to his comparison, he tweeted, reminded him of when he had said, "I don't have to read Mein Kampf to condemn Nazism." "The numpties (fools) thought I was accusing Muslims of being Nazis!" he wrote.

At the time of publication, Ahmed had not responded to a CNN request for comment on Dawkins' remarks and had not commented via his verified Twitter account.