Hamas political chief Ismail Haniyeh on Saturday called for building a regional alliance to counter challenges facing the Palestinian cause.

"The Israeli occupation is the common enemy of the Islamic nation and the responsibility of the nation is to besiege the enemy and expose its crimes," Haniyeh said in a recorded message to the 32nd session of the Islamic Unity Conference in Tehran.

The two-day conference brings together a host of intellectuals and politicians from more than 100 countries from around the world.

A host of Iranian officials, including President Hassan Rouhani, are also attending the event.

Haniyeh underlined the importance of criminalizing all attempts to normalize ties with Israel.

"The only enemy of the nation is Israel, which occupies the Palestinian land and desecrates Islamic and Christian holy sites," Haniyeh said.

The Hamas leader went on to call for adopting an Islamic strategy to counter all Israeli schemes and enhance Palestinian steadfastness in the occupied city of Jerusalem.

"All forms of resistance remain our strategic option," Haniyeh stressed.