(CBS/AP) WASHINGTON - The U.S. is levying new sanctions on a key Syrian bank as it seeks to ratchet up economic pressure on President Bashar Assad's regime amid ongoing violence and seemingly stalled diplomatic efforts to bring peace.
The Treasury Department said the Syria International Islamic Bank has been acting as a front for other Syrian financial institutions seeking to circumvent sanctions. The new penalties will prohibit the SIIB from engaging in financial transactions in the U.S. and will freeze any assets under U.S. jurisdiction.
The tightened sanctions come as the U.S. grapples for ways to quell deadly violence in Syria and spur a political transition. The U.S. and at least a dozen other nations expelled Syrian diplomats Tuesday in response to the weekend massacre of more than 100 villagers - many of them women and children - in Houla, Syria.
U.N. observers discovered an additional 13 bound corpses in eastern Syria Wednesday, many of them apparently shot execution-style, the international monitoring mission said Wednesday.
The U.N. Security Council will meet Wednesday to discuss the situation. The international body's top human rights body also will hold a special session Friday on the recent wave of killings, officials said. The Syrian government denied its troops were behind the attacks and blamed "armed terrorists."
Human Rights Council spokesman Rolando Gomez said the session will be called based on a request supported by 21 of the 47 nations that are council members. The request, he said, required support from at least a third of its members and was officially submitted by Qatar, Turkey, the United States, Saudi Arabia, Kuwait, Denmark and the European Union.
The Geneva-based council rarely holds such sessions but has done so several times since the Arab Spring revolutions last year to discuss dire human rights situations in Libya and Syria. Its actions are often used to lend weight to efforts at the U.N.'s most powerful body, the Security Council in New York, to demand an international response.
The United States says it remains opposed to military action in Syria. The massacre has provoked strong global condemnation, but it is unlikely to trigger a military assault similar to last year's NATO-led campaign in Libya to oust its leader, Muammar Qaddafi.
A U.S. State Department spokesperson has said the United States will keep up pressure at the Security Council, where it holds one of five veto-wielding seats, to find ways to stop the violence by Syrian President Bashar Assad's forces.
As permanent Security Council members, Russia and China have used their veto power to block U.N. resolutions against Assad. The U.S., France and Britain hold the other permanent seats. Russia, which has been especially crucial to Syria in providing a buffer from international action, has grown increasingly critical of Damascus in recent months and condemned the Houla massacre, but also criticized the expulsion of Syrian diplomats.
"The banishment of Syrian ambassadors from the capitals of leading Western states seems to us to be a counterproductive step," Russian Foreign Ministry spokesman Alexander Lukashevich said. He said the move closes "important channels" to influence Syria.
The U.N. human rights office said Tuesday that most of the 108 victims in the town of Houla were shot at close range, including 49 children and 34 women, and entire families were gunned down in their own homes.
Last week, a U.N. panel of independent human rights experts said the Syrian regime and an increasingly organized rebel force are carrying out illegal killings and torturing their opponents but found that government forces are still responsible for most of the violence in the uprising.
A cease-fire declared in April has been violated daily by both sides in the conflict as more than 250 U.N. observers based in cities around Syria scramble to monitor a peace plan brokered by international envoy Kofi Annan.
Annan met with Assad on Tuesday in Damascus to try to salvage what was left of his peace plan, which since being brokered six weeks ago has failed to stop any of the violence on the ground.
Reacting to the recent diplomatic maneuvers, the Al-Baath daily, the mouthpiece of Assad's Baath Party, said Syria won't be intimidated by the by such "violent rhythms" and would remain standing in front of such "ugly, bloody and dramatic shows." It added that "Syria will not tremble as they think."
The government's Al-Thawra newspaper also blasted the Western decision, calling it an "escalation that aims to besiege Annan's plan and enflame a civil war."
Tensions have escalated as more information emerges about the May 25 killings in Houla.
The U.N.'s human rights office said most of the 108 victims were shot execution-style at close range, with fewer than 20 people cut down by regime shelling.
U.N. peacekeeping chief Herve Ladsous said there are strong suspicions that pro-Assad fighters were responsible for some of the killings, casting doubt on allegations that "third elements" or outside forces were involved, although he did not rule it out.
Meanwhile, activists said Syrian troops shelled restive suburbs of Damascus and rebel-held areas in the central city of Homs on Wednesday.
The Britain-based Syrian Observatory for Human Rights and the Local Coordination Committees said at least five people were killed in the Damascus suburb of Douma. Both groups had no details about casualties in Homs, which is the provincial capital of the province that includes Houla.