In Riyadh on Friday, Secretary of State Hillary Clinton urged Saudi Arabia to support diplomatic efforts to resolve the crisis in Syria. The kingdom, a key American ally in the Middle East, has reportedly pressed Jordan to allow weapons across their border into Syria.

Clinton met with Saudi king Abdullah who, along with other Arab Gulf leaders, has condemned the bloodshed in Syria where for more than a year, President Bashar al-Assad has deployed heavy force against protesters. Their demonstrations have since morphed into armed resistance — a civil war that appears to break down along sectarian lines.

Syria’s Sunni Muslims, who compromise roughly 70 percent of the population, form the backbone of the insurgency while minorities and coastal business elites tend to be wary of regime change, fearful that their freedoms will be crushed if the Sunni majority comes to power.

Saudi Arabia, itself a Sunni power, supports the uprising because Assad is an ally of Iran’s, the kingdom’s main rival for regional hegemony.

In January, the emir of Qatar, another Sunni monarch, suggested that “to stop the killing” in Syria, “some troops should go.” A military intervention seems unlikely but Saudi Arabia has warmed up to the prospect of providing arms to the Syrian opposition. Prince Saud bin Faisal Al Saud, the Saudi foreign minister, told representatives of the “Friends of Syria” last month that arming the rebels would be an “excellent idea.”

Some reports suggest that Saudi weapons are already underway. Turkey and the United States are willing to supply only “nonlethal” assistance, possibly including aid and communications.

The Friends of Syria, nations that sympathize with the uprising, meet against in Istanbul on Sunday. The conference is designed to demonstrate resolve and orchestrate action among Arab and Western states against the Ba’athist regime in Damascus.