Cairo sent invitations Thursday to Fatah and Hamas for the signing of the reconciliation agreement announced Wednesday, the Maan news agency reports.

The deal comes after 18 months of failed unity talks between the bitter rivals.

PA Chairman Mahmoud Abbas and Hamas Prime Minister Khaled Mashal are expected to be on hand at Teusday's signing ceremony to formalize the agreement.

Walid Al-Awad, politburo member of the leftist Palestine’s People’s Party, said the quick ratifications was needed to stave off attempts at "“cutting off the road to any attempt to obstruct it or to backtrack on it.”

It was widely reported in 'Palestinian' news services over the past several months that the Hamas rank-and-file is opposed to reconciliation with Fatah.

 Israeli observers have suggested the reconciliation may be short lived.

Secretary General of the National Reconciliation Committee Iyad As-Sarraj said ratifying the agreement will “open the door for political partnership."

As-Sarraj said his committee has made “intensive contacts between all of the parties over the past two years to achieve reconciliation."

Hamas leader Ismail Radwan said Thursday the deal would be ratified in the presence of party leaders as a "practical response" to Israeli threats attempting to derail the process.

"We can best deal with the threats by signing and implementing the agreement," Radwan said in a statement.

The invitation to the signing ceremony comes amid what appears to be a dangerous crossroads in Egyptian-Israeli relations.

Officials in Cairo, when brokering the deal, where aware its terms would be unacceptable to Israel and likely represents an implicit backing of unilateral PA moves outside the Oslo-framework to secure a declaration of statehood from the United Nations.

Israel's prime minister Binyamin Netanyahu has consistently maintained the exclusion of Hamas from the PA is one of his conditions for the creation of a PA state on Jewish land.

Cairo recently announced it would be pursuing policies "more acceptable to public opinion." A recent survey by a US research institute revealed 54% of Egyptians want to annul Egypt's peace treaty with Israel, which they believe is a negative aspect of the Mubarak-era.

Anti Israel-Egypt peace protests were held this week.

Egypt has said it will be sending "advisers" to Gaza to aid in implementing the reconcilliation agreement.

Israeli officials have made it clear there will be no talks with a PA government that includes Hamas.