Rand Paul made the comments in support of US President Donald Trump who previously said Ilhan Omar and three other Democratic congresswomen should 'go back' to where they came from.
Just weeks after US President Donald Trump drew condemnation for telling four Democratic congresswomen to "go back" to where they came from, a Republican senator offered to buy one of them a plane ticket to Somalia.
In an interview with Breitbart News last week, Rand Paul said he did not want to force Ilhan Omar to go anywhere but offered to contribute to her plane ticket so she could "maybe learn a little bit about the disaster that is Somalia".
"That has no capitalism, has no God-given rights guaranteed in a constitution, and has about seven different tribes that have been fighting each other for the last 40 years,” he said.
"And then, maybe after she’s visited Somalia for a while, she might come back and appreciate America more."
Mr Trump's initial remarks were officially condemned as "racist" by the US House of Representatives earlier this month, with four members of the Republican party voting alongside 235 Democrats and one Independent.
Defending his party leader's comments, Senator Paul told Breitbart News that Ms Omar was as "ungrateful as you can get".
"I hear Representative Omar say 'oh, America's a terrible place, I'd love to be justice and there's no justice here', well she came here, we fed her, we clothed her, she got welfare, she got school, she got healthcare," he said.
"And she has the honour of actually winning a seat in Congress and she says we are a terrible country?"
Three of the four congresswomen referenced by Mr Trump were born in the US and are of African-American, Hispanic and Arab descent.
Ms Omar, who was also the target of chanting by supporters of the US president calling to "send her back", was born in Somalia but migrated to the US as a refugee in 1992, becoming a citizen in 2000.
Following the statements, Ms Omar retweeted a post that appeared to reference a 2017 incident in which Senator Paul was tackled to the ground by his neighbour following a dispute over a pile of debris. His attacker was sentenced to 30 days in jail in 2018 and forced to pay a $10,000.
"Imagine being Rand Paul's next door neighbor and having to deal with @RandPaul's lying cowardly circular whiney bullcrap about lawn clippings. No wonder he ripped his toupee off," the tweet read.
Social media users and Donald Trump Jr were quick to condemn the move, claiming Ms Omar was supporting violence.
Mr Trump has repeatedly denied that his tweets were racist, tweeting earlier this month that he did not "have a racist bone" in his body.