SCHEVENINGEN, Netherlands -- A coalition including the United States, the European Union and the Arab League met Thursday to plot new ways of isolating the regime of Syria's President Bashar Assad, as a Syrian opposition leader warned that sanctions alone won't bring the regime down.The group called "Friends of the Syrian People" was set up in February after the U.N. Security Council was unable to reach agreement on a resolution condemning Syria's government, due to opposition from Russia and China.On Thursday, financial experts joined representatives of the group at their meeting in The Hague, Netherlands, to help member countries understand how Syria may be using dual-use technologies and front companies to get around the existing sanctions, which include an embargo on oil and arms trade with Syria by participating nations. Twelve more countries have joined the 60-member coalition, committing also to block Syrian financial transactions, and enforce a travel ban on the country's top leaders.The uprising against the Syrian government began in March 2011 as part of Arab Spring protests, and intensified after Assad's government used the country's military in an attempt to end them with violence. The United Nations estimates that at least 18,000 people have been killed as a result of the fighting, most of them civilians. More than 1.5 million people have been displaced, many fleeing as refugees to neighboring countries such as Turkey and Jordan.Dutch Foreign Minister Uri Rosenthal said the sanctions are having an effect, despite non-participation by Russia, China and Iran, citing sharp fall in Syria's oil exports."The EU took 90 percent of Syria's oil," before the sanctions were applied, he said. "It turns out to be hard for the regime to sell oil elsewhere."Abrahim Miro, a member of the Syrian Governing Council - an umbrella organization of Syrian opposition groups cooperating to overthrow the government - said that the sanctions alone will not bring Assad's regime down. He said the sanctions, together with armed resistance by the Syrian Free Army "will actually cause the economic heart attack and also the military heart attack of the regime."Miro said that Syria's continued trade with Iraq and Iran - which were not present at the Thursday meeting - is a major source of concern for the opposition.Abdo Hussameldin, a former official in Syria's oil ministry, who in March became the highest-ranking member of the government to defect, said that the economic sanctions were demoralizing and delegitimizing the regime in the eyes of the country's people. But he agreed with Miro that the sanctions alone won't force Assad from office as long as his regime continues to get financial support from countries such as Russia, Iraq, Iran, Venezuela and Lebanon.