British Prime Minister David Cameron and other European leaders have announced plans to join French President Francois Hollande at a unity rally in Paris.

The rally Sunday comes after the massacre of 12 people at the Charlie Hebdo satirical newspaper in Paris, and two hostage-taking incidents that left four hostages dead.

Cameron said on Twitter Friday the event will "celebrate the values" of the publication.

Italian Prime Minister Matteo Renzi, Spanish Prime Minister Mariano Rajoy and Finnish Prime Minister Alexander Stuff also indicated on Twitter they would attend.

Other national leaders are expected, as are many leading French political figures.

The terrorist attack was seen by many as an attack on free speech and has shocked France.

The main suspects in the attacks were killed Friday.