Hariri announced his resignation on Saturday in a televised speech from Riyadh.
He said he feared for his life and accused Saudi Arabia's arch-rival Iran and its Lebanese ally Hezbollah of taking over his country and destabilising the broader region.
Hariri's announcement from Riyadh, which coincided with a Saudi purge of princes, ministers and a top businessman, sparked speculation in Lebanon that he quit under duress and was subject to Saudi movement restrictions.
Today the official WAM agency of the United Arab Emirates, a key Saudi ally, reported Hariri had met Sheikh Mohammed.
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The UAE strongman assured him of his country's "support" for Lebanon "in the face of regional challenges and interferences in its affairs".
His departure sparked concerns of a political crisis in Lebanon as Saudi Arabia and Iran face off over Yemen.
Hezbollah head Hassan Nasrallah said Sunday Hariri's resignation had been "imposed" by Saudi Arabia.
"It was not his intention, not his wish and not his decision" to quit, Nasrallah said in a televised address.
The Hezbollah leader also questioned why Hariri gave his resignation speech from Saudi Arabia.
"Is he at home? Will they let him return? These are legitimate concerns," he said, referring to a purge of princes, ministers and businessmen in Saudi Arabia in an anti-corruption operation.