The radical Islamist groups said on Monday they had narrowed their differences with Palestinian leader Mahmud Abbas over his calls for a ceasefire while insisting Israel would have to pay a price for peace. Abbas, who has been in Gaza since January 18 in a bid to persuade factions such as Hamas and Islamic Jihad to lay down their weapons, expressed confidence in a television interview Sunday that an agreement could be reached soon. Both groups echoed his optimism on Monday as a key mediator in their talks said that an unofficial "cooling down" period was already in place. "We have reached, in principal, agreement on important issues and the differences are very narrow," Mushir al-Masri, a spokesman for the radical Islamist group, told AFP. "Everyone on the Palestinian side is determined to have a collective position," he added.Abbas, elected president of the Palestinian Authority on January 9, is understood to be trying to tempt the factions into a change of strategy by dangling the carrot of participation in the political process. While both Hamas and Jihad boycotted the presidential contest they have agreed to take part in July's legislative elections and in municipal polls which are due to take place in Gaza later this week.