Texas Senator Ted Cruz may have won the Iowa caucuses, but he is not winning new friends, especially among her Republican presidential rivals.

Retired neurosurgeon Ben Carson, who used to be one of the top contenders in the Republican presidential race, for instance went to the extent of quoting Bible verses recently to imply that Cruz is a false prophet.

In a news conference he called at the National Press Club, Carson took an apparent swipe at Cruz for supposedly using "deceptive Iowa Caucus tactics."

The retired neurosurgeon was apparently referring to news reports believed to have been released by Cruz camp about Carson supposedly taking a break from the campaign.

Cruz has already expressed his apologies for his remarks, saying he was not much aware of goings-on in Carson's campaign.

Carson accepted his rival's apology but said Cruz's explanation seemed unacceptable.

"Senator Cruz told me that he was not aware of that when I talked to him and that he did not agree with that kind of thing," Carson said.

"We'll wait and see what he does to demonstrate that. He could very well have not known about it. But it was obvious there were people in his organisation who not only knew about it, but who carried it out, who executed it," he added.

The retired doctor, who is a member of the Seventh-day Adventist Church, used a verse from the Gospel of Matthew, particularly the one which tells about the Sermon on the Mount.

"When I say, 'by their fruit you will know them,' that was the Sermon on the Mount," Carson said. "And it was in the context, what Jesus was saying, there are some people who aren't what they seem to be, who say one thing and do another. But you can always tell who they are by their fruit, how they act."

The Bible verse Carson quoted begins with the following sentences: "Watch out for false prophets. They come to you in sheep's clothing, but inwardly they are ferocious wolves. By their fruit you will recognise them."

Carson also urged the American public and the media to carefully scrutinise presidential candidates.

"We've always had a good way of evaluating people. Will we use it? Or will we ignore it?" he said.