U.S. Secretary of State Hillary Clinton will meet with Russian Foreign Minister Sergei Lavrov and U.N. peace envoy Lakhdar Brahimi Thursday to discuss the Syrian conflict.
A senior U.S. official said the trio will meet in Dublin, Ireland on the sidelines of a human rights conference.
The meeting comes as concern grows that Syria's government may be preparing to use chemical weapons against its own people.
United Nations Secretary-General Ban Ki-moon echoed Western warnings to Syria during a stop in Baghdad on Thursday.
"I have expressed my gravest concern to the government of Syria and I have sent a letter directed to President Assad in couple of days ago as I did in couple of months ago," said Ban. "I am very much in concern and I have that in any case of chemical weapons is used then whoever maybe will have to be brought to justice and will create serious consequence to those people.''
NBC News and Fox News in the United States, citing U.S. officials, are reporting the Syrian military has loaded precursor chemicals for deadly sarin gas into aerial bombs and is awaiting for the final order.
U.S. Defense Secretary Leon Panetta said Thursday "the intelligence that we have raises serious concerns that this is being considered."
Panetta warned that Syria's use chemical weapons "will cross the red line," though he declined to say what the consequences would be.
Syrian Deputy Foreign Minister Faisal Maqdad dismissed the expressions of alarm. He told Lebanon's Al-Manar TV that Western countries are raising the threat of chemical weapons as an excuse to intervene.
"If Syria had chemical weapons, these weapons would definitely not be used against the people of Syria," said Maqdad. "We have strong fear of the existence of a conspiracy to use the weapons; by the United States and some European states, which might have supplied such weapons to terrorist organisations in Syria, in order to claim later that Syria is the one that used these weapons.''
Violence meanwhile, continues to flare in the Syrian capital of Damascus.
A car blew up Thursday in front of the headquarters for the Syrian Arab Red Crescent. Video posted to the Internet claims to show the burning vehicle.
Syrian state-run television blamed the blast on terrorists - the term the government uses for Syrian rebel forces - and said the blast did some damage to the building.
There are also reports of more shelling in the suburbs around Damascus.
Video posted on the Internet purports to show mortar shells falling on the northeastern suburb of Madyara.
Other video shows residents lining up for bread, some of the lines extending for several blocks.
Also Thursday, Germany's Cabinet agreed to send Patriot air defense missiles and troops to Turkey to help protect the NATO member from possible Syrian attacks.
The agreement must now be approved by the German Parliament, which is expected to endorse the measure. The Netherlands and the U.S. also are expected to help deploy Patriot missiles in Turkey in the next few weeks.
NATO decided earlier this week to send the missile-defense system to Turkey.