"Do whatever you want. Manufacturing the holy weapons is our mission and we know how to acquire weapons," Abu Ubaida, a spokesman for Hamas' armed wing, told a news conference.
Addressing journalists with his face masked by a checkered Arab scarf, he said that only 48 Hamas fighters were killed in the IDF operation in Gaza. Palestinians report that at least 1,300 people were killed in the Strip in the past three weeks, while Israel claims that at least 500 of them are Hamas members.
Abu Ubaida went on to say that "all options would be open" if Israel failed to pull its troops out of the Gaza Strip within a week, a demand raised by Hamas when it announced on Sunday a ceasefire after three weeks of fighting.
Iranian President Mahmoud Ahmadinejad telephoned Hamas politburo chief Khaled Mashaal on Monday and congratulated him on his "victory" in the battles against Israeli soldiers in the Gaza Strip, the Iranian Students News Agency (ISNA) reported.
According to the report, Ahmadinejad telephoned Mashaal and told him, "This is only the beginning of victory." He added that "pressure must be exerted for a complete withdrawal" of the IDF soldiers from the Strip and for the opening of the Gaza crossings.
The Iranian president went on to say that "the Zionist criminals must be prosecuted".
Israel, which has declared its own ceasefire, has threatened to renew military action if Hamas tries to smuggle more weapons into the Gaza Strip.
Israel wants Egypt to prevent arms from reaching Palestinian militants through tunnels running under the border with the Gaza Strip.
On Friday, Israel signed a security accord with the United States that calls for increased information-sharing, technical assistance and the use of various US "assets" to prevent weapons from getting to Hamas from air, land or sea.