ISTANBUL, Turkey - Pro-Palestinian activists, marking the first anniversary of a deadly raid by Israel on a Turkish aid ship bound for the Gaza Strip, gathered Monday on the deck of the same boat, refitted and preparing to sail for Gaza again next month.

An international coalition of activists said Egypt's removal this past weekend of a four-year blockade of Gaza would not affect their plans for a new flotilla, which will depart from various European ports to try to breach Israel's sea blockade.

Israel says the blockade stops weapons from reaching Hamas extremists, but activists call restrictions on Gaza's 1.5 million residents a human-rights violation.

"The Gaza shore has to be free. That's why we are sailing there," Vangelis Pisias, a Greek organizer, said at a news conference on the Mavi Marmara.

Last May 31, Israeli commandos boarded the ferry before dawn. Nine activists died in the botched commando operation, with each side accusing the other of starting the violence.

Pisias said the aid convoy would sail in "20 days," though IHH, the Islamic aid group that operates the Mavi Marmara, has said only that the third week of June was the target date for departure. That would allow Turkey to proceed with parliamentary elections June 12 without fear of a possible confrontation at sea that would likely disrupt the electoral debate and distract Turkey's leadership.

Late Monday night, crowds marched to Istanbul's Taksim Square to commemorate the nine slain activists with songs, speeches, and prayers.

Israeli military officials have said troops have been training for months to intercept any flotilla, and plan to use different tactics this time. The officials declined to elaborate. They spoke on condition of anonymity because of the secrecy of the planning.