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Secretary of State John Kerry said Monday the Syrian government is receiving support from multiple nations including Iran and warned the window of opportunity for a diplomatic solution to the Iranian nuclear problem "cannot by definition remain open indefinitely."

Kerry, who was meeting in Riyadh with the foreign ministers of Kuwait, Bahrain and Oman as well as the Saudi crown prince and foreign minister, added that "there is time to resolve this issue providing the Iranians are prepared to engage seriously" on proposals to defuse it.

"But talks will not go on for the sake of talks and talks cannot become an instrument for delay that will make the situation more dangerous," he said. Kerry said he and Saudi Foreign Minister Prince Saud al-Faisal "discussed our shared determination to prevent Iran from acquiring a nuclear weapon."

Saud said that Saudi Arabia "supports the efforts to resolve the crisis diplomatically in order to alleviate all doubts surrounding the program."

"Therefore, we hope that the negotiations will result in putting an end to this problem rather than containing it," he said, "taking into account that the clock is ticking and negotiations cannot go on forever."

In addition to Iran, Kerry, who is on his first overseas trip as secretary of state after succeeding Hillary Clinton, also held discussions about the situation in violence-torn Syria.

Kerry said that unfortunately the "bad actors" in Syria are receiving support from Iran, Hezbollah and Russia.

"The United States will continue to work with our friends to empower the Syrian opposition to hopefully be able to bring about a peaceful resolution, but if not, to increase pressure on Assad," he said. The United States last week agreed to increase non-lethal aid to Syrian opposition groups.

Saudi Arabia and several other Gulf states are believed to be involved in shipping weapons to Syrian rebels, who have yet to receive lethal aid from the West.

"The Kingdom stressed the importance of enabling the Syrian people to exercise its legitimate right to defend itself against the regime's killing regime," Saud said.

Saud said that Syrian President Assad has lost all authority, saying he has never heard of a regime that would use missiles against innocent women and children in cities.

"Saudi Arabia will do everything within its capacity, and we do believe that what is happening in Syria is a slaughter," he said, "... and we can't bring ourselves to remain quiet. Morally we have a duty."

Kerry also was to meet in Riyadh with Palestinian leader Mahmoud Abbas, who is visiting the Saudi capital.

Kerry's working lunch with Abbas was coming two weeks before the secretary is to accompany President Obama to Israel, the Palestinian territories and Jordan to explore ways of restarting the Israeli-Palestinian peace process.

Kerry travels next to the United Arab Emirates and Qatar before returning to Washington Wednesday.

Fox News' James Rosen and The Associated Press contributed to this report.