GAZA CITY, Gaza Strip (AP) -- Four months after the Hamas takeover of Gaza, the usually hidden arguments between the group's rival camps were unexpectedly laid bare.

In a five-page letter posted Sunday on a Website affiliated with Fatah, former Hamas government spokesman Ghazi Hamad wrote that the takeover was a ""serious strategic mistake that burdened the movement more than it can bear.""
He said several Arab countries, led by Egypt, were trying to bring the sides together again. Egypt had played a key role in previous efforts to set up a coalition of Hamas and Palestinian President Mahmoud Abbas' Fatah.
However, one of the group's most powerful figures, Mahmoud Zahar, told The Associated Press that Hamas can run Gaza without difficulty despite harsh economic sanctions, and he suggested that a failure of U.S.-led peace efforts would only strengthen his group further.
Parliament election victory brought Hamas to power in March 2006. Gaza's 1.4 million people can no longer leave the territory, only limited supplies are allowed in, exports are frozen and some 100,000 private sector jobs have been lost since June.
Abbas has said he would resume dialogue with Hamas only if the group withdraws its forces from the security installations it seized in Gaza.
Hamas has declined to do so, but the head of the Hamas government in Gaza, Prime Minister Ismail Haniyeh has recently urged a resumption of contacts with Abbas.
He said, the Palestinian president, elected in 2005, is politically weak and does not have a mandate to negotiate with Israel.
Asked whether Abbas should step down, Zahar said: ""He should, he should, he should resign ... he is a very weak man, and his regime already failed. He should not go to any meeting with the Israelis and the others because he is not representing the majority (of Palestinians).""
Zahar said he is certain the U.S.-sponsored peace conference will fail, and suggested that this would weaken Abbas further. ""He met many times (with Israeli leaders), and what will be the end result on the popular level if he came back with a big zero?"" Zahar asked rhetorically.
In contrast, Palestinian negotiator Saeb Erekat of Fatah said last week that success of the conference would eliminate public support for Hamas.