Pakistani supporters of preacher Tahir-ul-Qadri protest against the killing of followers in Karachi on Thursday. As the cleric returned to Pakistan on Monday, his supporters engaged in violent clashes with police. Asif Hassan / Agence France-Presse

A prominent cleric arrived in Pakistan on Monday with the self-declared aim of leading a "peaceful democratic revolution" against the civilian government there, a process he started with mass rallies last year.

Tahirul Qadri, a Pakistani preacher who usually lives in Canada, was due to fly into the capital, Islamabad, but authorities diverted his flight to Lahore, away from his supporters, who had gathered to greet him.

The plane carrying Qadri circled above Benazir Bhutto International Airport near Islamabad for an hour and a half before it was diverted, as 2,000 of his supporters clashed with police, who fired tear gas and fought running battles.

Qadri is a divisive figure in Pakistan, where he made headlines last year by leading mass protests aimed at unseating the government.

"We want no corruption, we want no terrorism in our country," Qadri told Reuters aboard the plane. "We want total transparency of institutions."

Qadri's sudden ascent to prominence has prompted speculation that the army, which ruled Pakistan for decades, may be using him as a proxy in its efforts to sideline the civilian government.

His comeback comes at an uneasy time for Prime Minister Nawaz Sharif, whose civilian government has failed to engage Taliban militants in peace talks, prompting the army to launch a major offensive against them.

Even after the aircraft landed in Lahore, Qadri and his supporters refused to leave the plane, demanding it fly back to Islamabad or that the army send a representative to give him protection.

Qadri's spokesman Shahid Mursaleen said Qadri wanted to stage an Arab Spring-style revolt and install a government that would enforce reform, tackle terrorism and improve accountability.

"He wants to bring a peaceful democratic revolution," Mursaleen told Reuters. "He wants to topple the whole system."

It is hard to estimate Qadri's popularity in a country with few reliable opinion polls but his proximity to the army could catapult him to the center of a brewing protest movement.

Discontent with the government is already high due to power shortages that have crippled the economy, as well as a persistent Taliban insurgency, which stages attacks around the country.

Reflecting the government's anxiety, police cordoned off major roads leading to the airport serving Islamabad with cargo containers, and blocked mobile phone services to prevent protesters from communicating with each other.

At least eight people including a policeman were killed in Lahore last week when protesters clashed with police in a standoff over Qadri.

"Long live the army!" and "Revolution will come!" chanted his supporters who had gathered outside the airport in the military garrison city of Rawalpindi near Islamabad.