Hamas said Israeli fire killed two of its fighters in the northern Gaza Strip late Tuesday but Israel denied involvement in the incident. The victims were identified as Faraj Najjar, 29, and Ismat Moharra, 25.
One member was also hurt. The activists east of the town of Jabalya came under fire from a tank located on the Israeli border, the Palestinian group said. Earlier, Hamas said it was as an Israeli air strike.
However, according to Reuters, an Israeli military spokeswoman said: "There was no attack by the Israel Defence Forces in the Gaza Strip."
The men were believed to be involved in planting land mines on the Palestinian side of the border.