The TV report on Monday says Ayatollah Ali Khamenei held talks with Hamas' deputy chief, Saleh al-Arouri, who is heading the delegation. The Hamas delegation also met with Kamal Kharrazi, an adviser to Khamenei.
"Hamas is Iran's first line of defense," said Al-Arouri following the meeting.
The supreme leader issued a statement at the end of the meeting, calling the U.S. peace proposal - dubbed "the deal of the century" - a "dangerous plot" intended to destroy Palestinian identity with money.
"This is the main point that one should resist, and not allow them to eliminate the Palestinian identity using money ... several years ago, Palestinians were fighting using stones now they have precision rockets," he said.
The Iranian official news agency IRNA says al-Arouri's visit to Tehran follows a visit by senior Iranian parliamentary official Hossein Amir-Abdollahian to Lebanon last week.
Iran backs both Hamas and the Lebanese militant Hezbollah group.
Earlier on Sunday, Hamas rulers in Gaza condemned Israel's demolition of a Palestinian village Sur Baher on the outskirts of Jerusalem, which the Supreme Court ruled was an illegal construction.
The terror group called for intensifying "resistance" to the "the Zionist settlement project" in an official statement.
"The increase in the occupation's crimes against the residents of the holy city is a result of total American support," said Hazem Qassem, a spokesman for the militant group.