An aerial view of the Gaza Strip. Photo: Wikimedia Commons.

Norway has asked Israel to explain the legal grounds for detaining a Norwegian-flagged fishing boat seized while activists tried to sail with aid to the Gaza Strip, Norway‘s Foreign Ministry said on Tuesday.

The ministry said its diplomats in Israel had been providing consular assistance to five Norwegians who were among the 22 passengers and crew detained onboard the vessel Kaarstein on Sunday. Two Israelis on board were quickly released.

“We have asked the Israeli authorities to clarify the circumstances around the seizure of the vessel and the legal basis for the intervention,” the spokesman for the Norwegian Foreign Ministry in Oslo said.

A spokesman for Israel‘s Foreign Ministry declined to comment.

Torstein Dahle, head of the group Ship to Gaza Norway which organized the shipment, said it was the first Norwegian aid vessel to attempt to breach the Israeli blockade of Gaza.

The captain had been struck on the head by Israeli soldiers who ordered him to sail for Israel, but no one was seriously hurt, Dahle said.

“This is a peaceful boat; it’s impossible that it can threaten Israel‘s security,” he said.

The Gaza Strip is controlled by the Islamist terrorist group Hamas, which has fought three wars against Israel in the decade since taking power there.

Israel, citing security concerns that include fears of Hamas weapons smuggling, maintains a naval blockade of Gaza, and along with Egypt also restricts imports by land.

Numerous activist ships have been prevented from reaching Gaza in recent years.

Audun Lysbakken, leader of Norway‘s opposition Socialist Left party, called on the Foreign Ministry to protest against what he described as Israel “hijacking” the Norwegian boat in international waters.

Among those detained is Mikkel Gruner, a Danish citizen who lives in Norway and is the Socialist Left representative in the municipal council of the Norwegian city of Bergen.

Lysbakken said the activists had legal rights to protest against Israel‘s blockade, demanding the release of Gruner and the others.

A number of the groups involved in the latest flotilla — including the Turkish IHH and Malaysian MyCARE — are known for their ties with Hamas.

Furthermore, one of the organizers, Zaher Birawi, has been designated as a terrorist by the Israeli government, which has identified him as a Hamas representative in Europe.