The United States commended Muslim states for suspending Syria's membership in the Organization of Islamic Cooperation, saying it sent a "strong message" to President Bashar al-Assad's regime.
"Today's action underscores the Assad regime's increasing international isolation and the widespread support for the Syrian people and their struggle for a democratic state that represents their aspirations and respects their human rights," State Department spokeswoman Victoria Nuland said.
A statement issued at the end of an OIC summit meeting in the holy city of Mecca in Saudi Arabia said participants had agreed on "the need to end immediately the acts of violence in Syria."
The final statement also expressed "deep concern at the massacres and inhuman acts suffered by the Syrian people."
The OIC "sent a strong message to the Assad regime by suspending Syria's membership in the OIC," Nuland said.
"The United States commends the OIC for its action and commitment to a peaceful resolution in Syria."
On the sidelines of the summit, US special envoy Rashad Hussain met with OIC chief Ekmeleddin Ihsanoglu, President Asif Ali Zardari of Pakistan, Senegalese President Macky Sall, Malaysian Prime Minister Najib Razak, Vice President Namadi Sambo of Nigeria and Mauritanian President Mohamed Ould Abdel Aziz.
They discussed Syria, as well as others in the Arab Spring series of popular uprisings against autocratic rulers in the Middle East and North Africa, and US engagement with Muslim communities, according to a State Department note.
Hussain's attendance of the meeting "demonstrates the United States' commitment to working with our partners in the international community to support the aspirations of the Syrian people and bring additional pressure to bear on the Assad regime," it added.
The move by the OIC, which represents 1.5 billion Muslims worldwide, is aimed at further isolating Assad's embattled regime, but its effect is seen as being largely symbolic.
Syria was suspended from the Arab League last year over its clampdown on the uprising that Assad characterized as a plot by Western and rival powers to overthrow his regime.
Saudi King Abdullah has presided over the meeting, attended by Iranian President Mahmoud Ahmadinejad, whose country has openly criticized the push to suspend Syria.