U.S. Secretary of State John Kerry is denying calling Israel "an apartheid state," which he reportedly said at a private meeting last week.

"I do not believe, nor have I ever stated, publicly or privately that Israel is an apartheid state or that it intends to become one," Kerry said in a statement, following calls for him to resign or publicly apologize.

"Anyone who knows anything about me knows that without a shred of doubt," said Kerry, according to Al Jazeera English.

However, Kerry said he did use a poor choice of words during his speech Friday to international experts of the Trilateral Commission.

"I have been around long enough to also know the power of words to create a misimpression, even when unintentional, and if I could rewind the tape, I would have chosen a different word to describe my firm belief that the only way in the long term to have a Jewish state and two nations and two peoples living side by side in peace and security is through a two-state solution," he said.

"I will not allow my commitment to Israel to be questioned by anyone, particularly for partisan, political purposes," he added.

The Daily Beast reported that Kerry warned that a "unitary state winds up either being an apartheid state with second-class citizens -- or it ends up being a state that destroys the capacity of Israel to be a Jewish state."

The site said it was given a recording of Kerry's speech, which sparked controversy in Israel and prompted one Republican senator to call for Kerry's resignation.

Senator Ted Cruz said that Kerry has "repeatedly demonstrated a willingness to countenance a world in which Israel is made a pariah."

He said Kerry should tender his resignation "before any more harm is done to our national security interests and our critical alliance with the state of Israel".

Veteran Republican senator John McCain said Kerry should clarify his comments and issue an apology.

The deadline for Palestinian-Israel peace talks ran out Tuesday after negotiations brokered by Secretary Kerry began last July.

Last week, Israel placed a moratorium on the talks after Palestinian President Mahmoud Abbas announced that his Fatah party and Hamas, a classified terrorist organization, is forming a unity government.