US President Barack Obama spoke to Prime Minister Benjamin Netanyahu about Iran Monday, a day after the Israeli leader warned Tehran could convert uranium into weapons-grade material within weeks.

The White House said in a short statement that the leaders discussed Iran, Israeli-Palestinian peace efforts and other key issues.

Secretary of State John Kerry later stressed diplomacy as the route to test.

Netanyahu warned on Sunday that Iran is capable of converting low-grade uranium to material suitable for use in a weapons program with weeks -- even as Washington pursues diplomatic efforts to ease the nuclear showdown.

"The important part stems from technological improvements which allow Iran to enrich uranium from 3.5 percent to 90 percent in a number of weeks," his office quoted him as saying at a cabinet meeting.

Netanyahu is demanding increased pressure on Iran and has expressed skepticism about a diplomatic opening pioneered by new Iranian President Hassan Rouhani which he has called a "charm offensive."

Iran is to hold a new round of talks on the issue with six world powers in Geneva on November 7-8. This follows a round this month that resumed long stalled negotiations.

Israel is demanding four conditions before international sanctions on Iran are eased: a halt to all uranium enrichment; the removal of all enriched uranium from its territory; the closure of an underground nuclear facility in Qom; and a halt to construction of a plutonium reactor.

The Obama administration has said it is important to test the sincerity of Iran's promise to hold serious discussions on a nuclear program that the West says is geared towards producing weapons -- a charge Tehran denies.

Kerry forcefully defended diplomacy as the way to try to resolve the dispute, in a apparent riposte to Israel.

In a speech Monday night at a disarmament forum, Kerry said the United States has "an opportunity to try to put to test whether or not Iran really desires to pursue only a peaceful program, and will submit to the standards of the international community in the effort to prove that to the world."

He added: "I suggest that the idea that the United States of America, as a responsible nation to all of humankind, would not explore that possibility would be the height of irresponsibility."

In response to the Israeli demand for more pressure, Kerry said "some have suggested that somehow there's something wrong" with giving diplomacy a chance.

"We will not succumb to those fear tactics and forces that suggest otherwise," Kerry said.