Singer Annie Lennox and other celebrities on Friday called on Israel to stop its air attacks on the Gaza Strip.
Speaking at a press conference in London Friday alongside activist Bianca Jagger, comedian Alexei Sayle and politicians including former London mayor Ken Livingstone, Lennox said violence could never be a solution to conflict.
Jagger called on US President-elect Barack Obama to condemn the Israeli air strikes. Israel is responding to rockets fired from Gaza by Hamas.
Protests have been held around the world condemning the Israeli strikes, which have killed more than 400 people and left 1,700 injured.
Demonstrators are due to march in London Saturday to call for an end to the violence.