Khalid Mish'al was speaking at a news conference in Moscow after talks with Russian officials, including Foreign Minister Sergei Lavrov.
Earlier, Lavrov warned the Hamas delegation led by Mish'al that it will have no future unless it transforms into a political institution.
Lavrov also urged Hamas to keep all previous agreements that Palestinian authorities have reached with Israel.
"I have some cautious hope that, having become now a legitimate political factor in the Palestinian and Middle East life, Hamas would reassess its new role…[and] reassess its responsibility before the Palestinian people," Lavrov said.
Russian President Vladimir Putin invited the group to Moscow after Hamas won a surprise victory in Palestinian elections in January.
(AFP, AP, Reuters)
