Khalil al-Hayeh, a senior Hamas official in Gaza, said Palestinians should move ahead with reviving the PLO even if elections cannot be held.
Hamas has said it will compete in such elections only if Israel guarantees it won't arrest Hamas candidates and the world accepts the results — conditions unlikely to be met.
"If Israel says no and America says no (to elections), let us go to the PLO and organize it," said al-Hayeh, a member of the movement's decision-making political bureau. "This is a good solution."
Mashaal said recently that he is willing to give Abbas time to explore the possibilities of reviving peace talks with Israel. Hamas' traditional position is that it will not get in the way of such negotiations, and that any deal would be judged in a referendum.
Hamas officials said they believe the Palestinian president will start negotiating a unity deal only if Kerry's latest initiative runs aground.
The 78-year-old Abbas considers the split a stain on his legacy and is eager to end it before he leaves office.
Mashaal has indicated in the past that he is willing to narrow the ideological gaps. Abbas strongly opposes violence, while Hamas has targeted Israel with suicide bombings, shooting attacks and rocket fire, though it has observed informal cease-fires for extended periods since 2005.
While unwilling to renounce violence formally, Mashaal has told Abbas that he has embraced the idea of "popular protests" against Israeli occupation.
Mashaal won re-election despite his clash with Gaza hard-liners last year, largely because of his close ties with Qatar, Turkey and Egypt, seen as key to Gaza's survival and the Hamas quest for wider regional recognition.
Qatar has pledged $407 million in reconstruction funds for Gaza. Turkey is pressuring Israel to lift its remaining border restrictions on Gaza. Egypt brokered a cease-fire between Israel and Gaza to end an eight-day Israeli military offensive in November aimed at stopping rocket attacks by Gaza militants.
Hamas is a natural ally because the region-wide Muslim Brotherhood, Hamas' ideological parent, is influential all three countries.
In addition to cultivating foreign support, Mashaal managed to split the opposition against him during a visit to Gaza in December. As a result, Gaza Prime Minister Ismail Haniyeh was chosen as Mashaal's deputy, marking the first time someone from the Palestinian territories reached such a rank. Even though it was founded in Gaza in 1987, Hamas has traditionally been run by exiles.
Mashaal now has a stronger mandate but also faces new constraints. The Gaza branch of the movement enjoys veto power, and he'll have to listen closely to his international backers. Egypt and Turkey, for instance, both have diplomatic relations with Israel.
"His opponents became weaker than before," said Ahmed Yousef, a Hamas-linked intellectual in Gaza. "But that does not mean he will find a paved road for whatever he would like to suggest. It will be a bumpy road all the time."
Mohammed Daraghmeh, based in Ramallah, has covered the West Bank and Palestinian politics since 1996. Laub, the AP chief correspondent for the Palestinian territories, has covered the Mideast since 1987.
Follow Laub at www.twitter.com/karin_laub .