"Any regional or international attempt to lay siege to Hamas or its armed wing is bound to fail," said Marwan Eissa, a commander of the Ezzedine al-Qassam Brigades armed wing.
Hamas was "not looking for confrontation" with Israel, he said, quoted by Hamas-run news agency Al-Ray.
"But we are making sure our forces are reinforced in case of a confrontation. We're continuing to make rockets."
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Hamas fired thousands of rockets at Israel during a July-August conflict in and around the Gaza Strip when an Israeli military campaign killed nearly 2,200 Palestinians, most of them civilians.
Militant fire killed 73 people on the Israeli side, mostly soldiers.
Six months after the conflict ended, there has been no reconstruction of Israeli-blockaded Gaza and more than 100,000 Palestinians are still homeless.
Hamas has been struggling to pay its security forces due to Egypt's destruction of cross-border tunnels used to ferry in supplies.