At least six of those killed in the massacre belonged to the group, which led to mass protests in the occupied West Bank.
"The eyes of cowards do not sleep. If some have accepted humiliation, weakness and indignity for themselves, then by God we do not accept anything but pride, dignity and strength," the group said on Telegram Thursday.
"We know that grief has pervaded the country over the loss of our men, but we continue, since only yesterday, and after the funeral of our martyrs, nearly 50 new fighters joined the groups of the Lions' Den, so who can stop the Lions’ Den?"
It called on Palestinians to engage in the resistance against Israeli occupation.
"We can say to our people now, and after Tulkarm's accession to the armed resistance and the completion of the formation of its cells, the resistance in the West Bank now has a shield and a sword," the Palestinian group said in the statement, in reference to a town in the occupied territory’s northwest.
"We say to the [Israeli] occupation, you will spend a lot of time studying, researching, and analysing in order to understand the phenomenon of the [Lions'] Den, and then after all that you will fail, but we will not fail."
On Thursday, Lions' Den called on Palestinians to take to the streets across the occupied territories to commemorate those killed on Wednesday. Thousands of Palestinians protested across the West Bank, occupied East Jerusalem, the besieged Gaza Strip, and within Israel.
The Lions' Den is a newly formed armed Palestinian group that emerged in August in Nablus.
Following a number of incidents that saw Israeli soldiers killed by the group, the Israeli army carried out a large-scale military operation in October, targeting the group’s fighters in Nablus.
The entire city and surrounding areas were put under siege, with heavy restrictions on the movement of 430,000 Palestinians for several weeks.