Gerry Adams laying a wreath at the tomb of Yasser Arafat in 2006
Sinn Féin leader Gerry Adams will not be allowed to enter Gaza this week because he plans to meet members of Hamas, Israeli officials have said.
Foreign Ministry spokesman Yigal Palmor said Israel "would not help Adams meet with Hamas terror leaders."
Hamas, which rules Gaza, is listed as a terrorist organization by Israel, the US and EU.
A Sinn Fein spokesman said Mr Adams and his delegation planned to visit Gaza on Wednesday.
He added that: "We will meet with whoever wants to meet us."
Before Mr Adams set off for the Middle East Israeli officials said they would not meet him because he would not rule out meeting Palestinian militants.
Mr Adams said he intended to visit Gaza to witness damage caused by Israel's recent military offensive.
The Sinn Féin leader, who last visited the Middle East in 2006, said he regretted the Israeli government's refusal to meet him.
"As the leader of a party which was censored and demonised and whose members were killed, I see dialogue between all sides as key to building a successful peace process," he said.
"So I will meet with all sides and urge all sides to end all armed actions and to engage in meaningful dialogue.
"I believe there should be a complete cessation of all hostilities and freedom of movement for everyone."
Mr Adams said there were "similarities" between the Northern Ireland peace process and the Middle East, but "there are also significant differences".
"But it is clear that finding solutions will require leadership on both sides, and a willingness to take risks, initiatives, and compromise," he said.
"And it will need the international community, and particularly the USA, to play a very positive and active role."
In recent weeks several senior officials from the United Nations, as well as a US politicians have visited Gaza, entering through Israel. They did not meet with Hamas officials.