The invitations to Sunday's Christmas reception did not include Nusseibeh's official title, unlike the invitations to the Eid al-Fitr event, his spokesman said.
The attacks took place as crowds prepared for mass morning prayers to mark Eid al-Fitr, the Muslim celebration at the end of the fasting month Ramadan.
Khamenei, speaking on the first day of Eid al-Fitr, a festive end to the Muslim holy month of Ramadan, countered by comparing Obama to his predecessor.