ISTANBUL (AFP) - Syrian dissidents gathered here on Tuesday set up a broad-based "national council" to coordinate their campaign to topple President Bashar al-Assad, an activist said. The panel was formed after four days of discussions in this Turkish metropolis, the Syrian opponents told a press conference. "We have given martyrs and some of us are injured... With all these efforts and sacrifices, as a result of this responsibility, a sense of unity has been formed," activist Ahmad Ramadan said. "The council will convene in about two weeks to elect the chair and secretary... When it convenes it will adopt its bylaws," added Louay Safi, a US-based political scientist. The dissidents declined to give out the names of council members and said the body, which brings together all opposition groups both from inside and outside Syria, will elect them after its first meeting. EU governments formally adopted sanctions on Tuesday against 15 more people and five businesses, but stopped short of concrete moves to impose a full oil embargo on Damascus. The list of names covered by asset freezes and travel bans now runs to 50 people and nine businesses, with legal enforcement entering play when they are published in Wednesday's legislative log, the EU's Official Journal. But a diplomat told AFP on Tuesday that despite a first discussion in Brussels on the oil embargo, "no clear decision has yet been taken", with London in particular determined to ensure that sanctions do not impact on the Syrian people.