Story highlights Ted Cruz is beating Donald Trump 24%-19% in a new poll of Iowa Republicans

The poll found Cruz drawing support from many of the same voters who had been supporting Ben Carson before

Washington (CNN) Ted Cruz has overtaken Donald Trump in Iowa, according to a Monmouth University survey of Iowa Republicans released Monday.

If the caucuses were held today, Cruz would win with 24% support to Trump's 19% backing. Marco Rubio comes in a close third with 17% and Ben Carson , who was beating Trump 32%-18% in the last Monmouth University poll, has fallen to 13% support.

Behind the Cruz surge is support among evangelicals -- a decisive voting bloc in Iowa -- who selected Cruz over Trump 30%-18%.

Monmouth poll director Patrick Murray attributed Cruz's rise to Carson's fall in the early nominating state, but also noted that Iowa Rep. Steve King's endorsement likely had an impact. Nearly 20% of respondents said that King's endorsement made them more likely to support Cruz.

Read More