Senior Hamas official Mahmud Zahar slammed a Palestinian unity deal as a "mistake" that has thrown the Islamist movement into crisis, in an interview with Egypt's official MENA agency published on Sunday.
Hamas leader Khaled Meshaal signed an agreement with Palestinian president Mahmud Abbas earlier this month placing Abbas at the head of an interim government charged with organising elections later this year.
The decision to have Abbas head the government "is a mistake," Zahar told MENA. "No one inside the Hamas movement was consulted."
The deal signed in Qatar ends a long-running disagreement over the premiership that stalled Palestinian reconciliation, but Zahar said that "practically it can not be implemented."
"If the consultations took place among the small circle around the political bureau (headed by Meshaal abroad), then this is unacceptable," he said.
The agreement "needs to be reviewed, so Hamas leaders at home and abroad will meet over the issue in the coming two days."
He said after a series of discussions with Hamas officials and MPs "we found that many feel there is a real crisis."
The agreement struck by Meshaal's foreign-based leadership with Abbas's secular Fatah faction has run into serious opposition from Hamas members inside the Gaza Strip, which the movement has controlled since ousting the president's loyalists in 2007.
Members of the Hamas majority in the Palestinian parliament called on Thursday for the scrapping of the deal on constitutional grounds.
"After examining the question of Mahmud Abbas taking on the premiership as well as the presidency" and consultation with judicial experts, such a scenario was found to be contrary to the Basic Law, 31 MPs said in a statement.
The so-called "Doha Declaration" is the latest attempt by the rival movements to implement a reconciliation deal signed last April.
The declaration calls for a government of "independent technocrats" to oversee reconstruction efforts in Hamas-ruled Gaza and to "facilitate the implementation of presidential and parliamentary elections."
The Palestinian territories were effectively split in two -- a Hamas-controlled Gaza Strip and a Fatah-dominated West Bank -- when Abbas loyalists were ousted from Gaza in 2007.
Zahar said the sweeping Hamas victory in 2006 Palestinian parliamentary elections meant there was no reason to make concessions to Fatah.
"The people chose Hamas and rejected Fatah's programme. How can we at the last minute come and say that the Fatah programme proved to be a success and Hamas failed?" he asked.
"In fact, the reality is that the Hamas programme proved to be a success, with the Arab Spring and the Arab and Islamic opening in the region breaking the political embargo on Gaza."