Cyprus' Merchant Shipping Department on Thursday prevented international activists from sailing to the Gaza Strip to deliver humanitarian aid in defiance of Israel's blockade of the Palestinian territory. Department chief Sergios Sergiou said that a fishing boat and a small ferry that the Free Gaza Group were to use for the trip from Cyprus to Gaza had not undergone safety inspections which would take "at least a few days" to complete. "It's a dangerous trip," Sergiou told the Associated Press. "The vessels must undergo a general inspection before they are allowed to go." But Free Gaza Group spokesman Ramzi Kysia said that both vessels were allowed to sail from Cyprus during the group's previous attempts to reach Gaza. The Free Gaza Group has already made five successful boat trips from Cyprus to Gaza since August 2008. Kysia said the fishing boat sailed to the Palestinian territory in August last year. The ferry set sail in January this year during Israel's three-week war in Gaza, but had to turn back a few hours into the trip after encountering mechanical problems. Sergiou could not explain why the vessels were previously allowed to leave Cyprus. Free Gaza spokeswoman Greta Berlin said she was "absolutely outraged", but that activists would not be deterred. Around 32 people including a former US congresswoman and an Irish Nobel laureate were to sail to Gaza to deliver 3 tons of medical supplies and 15 tons of cement. "We promised the people of Gaza we would come back and that we would not forget them," said Mairead Corrigan Maguire, who won the 1976 Nobel Peace Prize for her work with Catholics and Protestants in Northern Ireland. Israel launched the blockade on the Gaza Strip in response to persistent Palestinian rocket attacks against Israeli communities in the Western Negev. Despite the general closure, Israel has consistently allowed trucks carrying essential supplies and humanitarian aid to flow through the border with Gaza.