The Hamas terror group partially reopened a key crossing between the northern Gaza Strip and Israel on Monday, a day after shuttering the checkpoint while blaming the Jewish state for the assassination of one of its terror chiefs in the Palestinian enclave.

The terror group, which is the de facto ruler of the Strip, said the Erez Crossing would be open to anyone wishing to enter Gaza, but those leaving would remain restricted to senior politicians, the sick and families of prisoners.

Men between the ages of 15 and 45 are forbidden from leaving in all cases, while women of all ages who fall into the categories would be allowed to leave.

“From Monday morning, travel through the Beit Hanoun (Erez) crossing will be permitted temporarily for some categories,” a statement from Iyad al-Bozum, a spokesman for the interior ministry in the Palestinian enclave, said.

On Sunday a statement from the interior ministry in Gaza said it was shutting the crossing for an indefinite period as it investigated the killing Friday of Mazen Faqha, an official in charge of Hamas terror activity in the West Bank.

The move was seen as an effort to keep Faqha’s killers from exiting the enclave.

The group has blamed Israel for the mysterious assassination, but believes Gazans may have been involved as well, according to reports.

Israel, which has not commented on the killing, said Sunday that its side of the crossing remained open.

The Erez crossing is the only one between Gaza and Israel for people. Another crossing with Israel, Kerem Shalom, is used for goods.

Israel has maintained a blockade on Gaza for a decade but business people and humanitarian cases can often get permits to come and go through the Erez crossing.

Hamas Interior Minister Eyad al-Bosom said in a post on his Facebook page Sunday that Gazans who entered Israel for humanitarian reasons would be allowed back into Gaza.

Palestinians prepare to cross from Israel into the Gaza Strip at the Erez Crossing, September 3, 2015. (Yonatan Sindel/Flash90)

Palestinians prepare to cross from Israel into the Gaza Strip at the Erez Crossing, September 3, 2015. (Yonatan Sindel/Flash90)

Jerusalem says the blockade is necessary to keep Hamas, labeled a terror group by Israel and the US, from building up military capabilities. Palestinian terror groups in Gaza and Israel have fought three wars since 2008.

Gaza’s sole crossing with Egypt has also remained largely closed in recent years.

Faqha was shot to death on Friday near his home in Tel el-Hawa, a neighborhood in southwestern Gaza City, by assailants using a weapon equipped with a silencer. He was hit by four bullets to the head, Gaza reports quoted by Army Radio said.

Mazen Faqha, upon his release after the Shalit deal in 2011. (Screen capture Twitter)

Mazen Faqha, upon his release after the Shalit deal in 2011. (Screen capture Twitter)

Hamas officials have blamed Israeli intelligence agency Mossad for the killing of Faqha, 38, who was shot dead by unknown gunmen in the Gaza Strip on Friday.

According to Israeli media, Faqha was responsible for terror cells of Hamas’s militant wing, the Izz ad-Din al-Qassam Brigades, in the West Bank.

Israel jailed Faqha over suicide attacks that killed hundreds of Israelis during the second intifada, or uprising, between 2000 and 2005. He was serving multiple life times for orchestrating a 2002 suicide bombing in which nine Israelis were killed. He was released in 2011 along with more than 1,000 other Palestinians in exchange for Gilad Shalit, an Israeli soldier Hamas kidnapped during a cross-border raid into Israel and then held hostage in Gaza for five years.