GENEVA - The White House rejected on Friday Israel's criticism of a possible deal between Iran and the West, saying 'any critique of the deal is premature.' "There is no deal," said White House spokesman Josh Earnest.

The statement comes as a response to Prime Minister Benjamin Netanyahu's warning earlier on Friday, who said that a deal with Iran would be "a big win for the Islamic Republic, but a bad and very dangerous deal for peace and the international community."

Meanwhile, the trilateral meeting between U.S. Secretary of State John Kerry, European Union foreign policy chief Catherine Ashton and Iran's Foreign Minister Mohammad Javad Zarif has begun in Geneva. Zarif is expected to present the Iranian draft for an agreement.

German Foreign Minister Guido Westerwelle told reporters on Friday evening that "we still have our discussions, and [we are doing] our best."

Also on Friday, diplomatic sources told Reuters that Russian Foreign Minister Sergei Lavrov is expected to join talks in Geneva on Saturday. A Chinese delegation is also due to arrive on Saturday, but It is still unclear whether the foreign minister or his deputy will attend the meetings.

Kerry landed in Geneva at around 4 P.M. Friday, to help clinch an interim nuclear deal with Iran and ease a decade-old standoff. According to a U.S. State Department official, Kerry was invited to the Geneva talks by Ashton in an effort "to help narrow the differences" between Iran and world powers. The official demanded anonymity because he was not authorized to release the information.

Upon arriving in Geneva, Kerry said that Iran and the six world powers have not reached any deal yet. "I want to emphasize there is not an agreement at this point," Kerry told reporters shortly after arriving in Geneva. "I don't think anybody should mistake that there are some important gaps that have to be closed."

The top diplomat arrived from Tel Aviv, where he had made a previously-unscheduled visit to meet with Prime Minister Benjamin Netanyahu, amid tensions between the Israeli and Palestinians over negotiations for a peace agreement.

Following their meeting, Netanyahu held a press conference in which he called upon Kerry not to sign a deal with Iran at this round of talks.

"I call upon the secretary of state not to haste in signing, to wait and weigh it anew," said Netanyahu.

Diplomats said a breakthrough at this week's negotiations remained uncertain and would in any case mark only the first step in a long, complex process toward a permanent resolution of Iran's dispute with the West over its nuclear ambitions.

But they said the arrival of Kerry, along with British Foreign Secretary William Hague and French and German foreign ministers Laurent Fabius and Guido Westerwelle was a sign that the five permanent UN Security Council members and Germany may be closer to an agreement with Iran than ever before.