RAFAH, Gaza Strip (AP) — Chinese dissident artist Ai Weiwei is visiting the Gaza Strip as part of a documentary he is making about Middle East refugees.

The activist crossed into Gaza through Israel with a crew of 10 people on Tuesday. The film will highlight the plight of millions of Syrians who fled the civil war in their homeland to neighboring countries or took perilous voyages in boats to Europe. 

On Wednesday, Ai said he is including the Palestinian refugees in the film because they constitute "the longest history" of displacement and their numbers complicate any settlement of their cause. The number of Palestinians who were displaced during the 1948 war surrounding Israel's establishment, along with their descendants, is estimated at over 5 million people, according to the United Nations.

"The Palestinian refugees really play a very important factor in the whole refugee situation," Ai told The Associated Press. With such a big population, he said it is "not easy" to find a solution.

Ai's crew has worked on the documentary in Jordan, Turkey, Greece and several other countries that have hosted Syrian refugees.

In 2011, China detained Ai for 81 days for being an outspoken critic of its human rights record. Last year, he managed to move to Germany after Chinese authorities returned his passport. He is famous for works addressing human rights abuses, official corruption and the collision between Chinese culture and Western consumerism

The visit, Ai's first to Gaza, coincides with the 68th anniversary of what the Palestinians call the "nakba," or catastrophe caused by their displacement during the 1948 war.

"We have to come here to interpret this into our film," he said.

During the three-day visit, Ai and his team will be shooting in refugee camps in the Gaza Strip. They also will look at the worsening living conditions in Gaza, which has suffered under an Egyptian and Israeli blockade and the rule of the Hamas militant group. Israel and Egypt imposed the blockade after Hamas seized power in 2007, saying the restrictions are needed to prevent Hamas from importing weapons.

"The condition here is unbelievable," Ai said as his crew filmed Palestinians trying to leave Gaza through Egypt, which temporarily opened its border with Gaza for two days Wednesday after nearly three months of closure. "Gaza is really suffering from this isolation and blockade from all over," he said.

Ai said the film should be complete by the end of 2016, and he will organize an exhibition with works related to refugees before the opening of the documentary.