Palestinian leader Mahmoud Abbas approved on Sunday the Palestinian basic law, Palestinian Wafa news agency reported.
Abbas signed on the amended copy of the basic law that was passed by the Palestinian Legislative Council (PLC) last week, said Wafa.
The part of the basic law that was amended is that the period of presidency should be for four years, while presidential elections have to be set up every four years.
The basic law also said that the Palestinian parliamentary elections have to be held every four years and the PLC members are directly elected upon the election law.
The PLC has earlier revealed that Abbas was expected to issue soon a presidential decree that set Jan. 21, 2006 as the day for holding the second parliamentary elections.
The first parliamentary elections were held in January 1996.
However, the Islamic Resistance Movement (Hamas) has opposed the idea of holding elections in January 2006, and called for holding the elections before the end of 2005.