Former Chinese President Hu Jintao was unexpectedly escorted off the stage at China's 20th Communist Party Congress on Saturday, sparking speculation over why he was asked to leave.

The sudden departure happened just as the international media were allowed into Beijing's Great Hall of the people for the closing ceremony.

What do we know?

Party officials have given no explanation for Hu's sudden exit, which took place just before 2,300 delegates at the Congress voted unanimously to endorse Xi's "core" leadership position.

The frail-looking 79-year-old seemed reluctant to leave the front row of the stage, where he was seated next to current president President Xi Jinping.

During an exchange that lasted about a minute, a steward attempted to take a sitting Hu by the arm before being shaken off.

The steward then attempted to lift the former president up with both hands from under the armpits.

Hu briefly exchanged words with Xi — who succeeded him as president in 2013 — and Premier Li Keqiang before being led out of the hall.

Hu's departure marked a dramatic moment in the highly choreographed event and most of the delegates stared blankly ahead.

Online video footage of the incident was quickly blocked within China.

Why could he have been asked to leave?

Hu, who handed over the office of party general secretary to Xi a decade ago after two terms, was said to have reservations about the current Chinese president's ambitions.

Hu stands for the old "collective" leadership model that believes China should be run by representatives from different factions, with age and term limits, which Xi wants to override with a third term.

Emily Rauhala, a reporter for The Washington Post, wrote on Twitter, "Hard not to see this pic as the encapsulation of an era." 

She added, "A tragedy in one act."

The former president had appeared slightly unsteady last Sunday when he was assisted onto the same stage for the opening ceremony of the congress.

Xi set to cement grip on power

President Xi is all but assured of being formally announced on Sunday as the party's general secretary for another five years.

This will allow him to break an unofficial two-term presidential limit and cement his grip on power.

Xi's third term is due to be announced during the government's annual legislative sessions in March.

Since taking over from Hu a decade ago, Xi has become China's most authoritarian leader since Mao Zedong.

Xi crushed opposition to his rule inside and outside the party, with many of his rivals jailed on corruption charges, while showing no tolerance for any form of public dissent.

mm/ar (AFP, Reuters, dpa)