President Michel Aoun left Lebanon's presidential palace on Sunday, marking the end of his six-year term without a replacement, leaving the small nation in a political vacuum that is likely to worsen its historic economic meltdown.

As Aoun's term ends, the country is being run by a caretaker government after Prime Minister-designate Najib Mikati failed to form a new Cabinet following May 15 parliamentary elections.

Aoun and his supporters warn that such a government doesn't have full power to run the country, saying that weeks of “constitutional chaos” lay ahead.

In a speech outside the palace, Aoun told thousands of supporters that he has accepted the resignation of Mikati's government. The move is likely to further deprive the caretaker administration of legitimacy and worsen existing political tensions in the country.

Mikati responded shortly afterward with a statement from his office saying that his government will continue to perform its duties in accordance with the constitution.

Many fear that an extended power vacuum could further delay attempts to finalise a deal with the International Monetary Fund that would provide Lebanon with some USD 3 billion in assistance, widely seen as a key step to help the country climb out of a three-year financial crisis that has left three quarters of the population in poverty. While it's not the first time that Lebanon's parliament has failed to appoint a successor by the end of the president's term, this will be the first time that there will be both no president and a caretaker cabinet with limited powers.

Lebanon's constitution allows the cabinet in regular circumstances to run the government, but is unclear whether that applies to a caretaker government.

Wissam Lahham, a constitutional law professor at St. Joseph University in Beirut told The Associated Press that in his view, the governance issues the country will face are political rather than legal.

Although the constitution “doesn't say explicitly that the caretaker government can act if there is no president, logically, constitutionally, one should accept that because… the state and institutions should continue to function according to the principle of the continuity of public services,” he said.