When an interior ministry official denied them permission to board the ferry, the protesters sat down in front of the tiny island's town hall, blocking a main roads.
Lampedusa's Mayor Giusi Nicolini did not attend the ceremony after criticizing the decision to hold it so far from the island, and the mayor of Agrigento, Marco Zambuto, called it a "farce".
"The presence of the Eritrean regime offends the dead and puts in danger the living," read a banner held at the ceremony by Eritrean nationals living in Italy.
