First of all, it is not easy for Hamas to refrain all Palestinian militant groups from attacking Israel, said Gatas.

Israeli officials have said the Jewish state would consider the truce deal if Hamas could restrain Islamic Jihad and other smaller militant groups from attacking Israel.

However, violence in the Gaza Strip mounted on Monday, killing seven Palestinians including a mother and four of her children, which cast more shadow on Egypt's mediation efforts.

Meanwhile, Islamic Jihad (Holy War) movement's armed wing claimed responsibility for wounding four Israeli soldiers in northern Gaza Strip and for launching two homemade rockets from the area at southern Israel.

Hamas armed wing, al-Qassam Brigades, also said in a statement that its militants confronted the Israeli army forces in northern Gaza Strip and had launched several mortar shells and homemade rockets at Israel.

Following seven reported Palestinian deaths in an Israel Defense Forces (IDF) action on Monday, Israeli Defense Minister Ehud Barak said that Hamas is to blame for all the attacks on Israel from the Gaza Strip and the consequences of such attacks.

Deposed Palestinian Prime Minister Ismail Haneya, however, said in a statement that "the current Israeli military escalation against Gaza is an evidence that Israel is not interested in the efforts to agree on a ceasefire in the Gaza Strip."

Besides, some other thorny issues, such as the swap of prisoners and the operation of the border crossings of the Palestinian territories, also hinder the talks, said Gatas.

Ruling out the possibility of signing an official truce deal, Gatas said the two sides could only reach a "tacit" ceasefire.

If Israel signed an official deal with the Palestinian groups, it means the Jewish state recognizes Hamas movement which has always been listed as a terrorist group by Israel, said Gatas.