Pakistani police have filed terrorism charges against former Prime Minister Imran Khan, authorities said Monday, escalating political tensions in the country as he holds mass rallies seeking to return to office.

The terrorism charges come over a speech Khan gave in Islamabad on Saturday in which he vowed to sue police officers and a female judge and alleged that a close aide had been tortured after his arrest.

Khan himself appeared to still be free and had not immediately addressed the police charge sheet being lodged against him. Pakistan's opposition Tehreek-e-Insaf party, Khan's political party, published online videos showing supporters surrounding his home to potentially stop police from reaching it. Hundreds remained there early Monday.

Under Pakistan's legal system, police file what it known as a first information report about the charges against an accused to a magistrate judge, who allows the investigation to move forward. Typically, police then arrest and question the accused.

The report against Khan includes testimony from Magistrate Judge Ali Javed, who described being at the Islamabad rally and hearing Khan criticize the inspector-general of Pakistan's police and another judge. Khan went on to reportedly say: "You also get ready for it, we will also take action against you. All of you must be ashamed."

Khan could face several years in prison from the new charges, which accuse him of threatening police officers and the judge. However, he's not been detained on other lesser charges levied against him in his recent campaigning against the government.

The Pakistani judiciary also has a history of politicization and taking sides in power struggles between the military, the civilian government and opposition politicians, according to the Washington-based advocacy group Freedom House.

Khan came to power in 2018, promising to break the pattern of family rule in Pakistan. His opponents contend he was elected with help from the powerful military, which has ruled the country for half of its 75-year history.

In seeking Khan's ouster earlier this year, the opposition had accused him of economic mismanagement as inflation soars and the Pakistani rupee plummets in value. The parliament's no-confidence vote in April capped months of political turmoil and a constitutional crisis that required the Supreme Court to step in. Meanwhile, it appeared the military similarly had cooled to Khan.

Khan alleged without providing evidence that the Pakistani military took part in a U.S. plot to oust him. Washington, the Pakistani military and the government of Khan's successor, Prime Minister Shahbaz Sharif, all have denied that. Khan also has been carrying out a series of mass rallies trying to pressure Sharif's government.

On Sunday, the internet-access advocacy group NetBlocks said internet services in the country blocked access to YouTube after Khan broadcast a live speech on the platform despite a ban issued by the Pakistan Electronic Media Regulatory Authority.

Police arrested Khan's political aide, Shahbaz Gill, earlier this month after he appeared on the private television channel ARY TV and urged soldiers and officers to refuse to obey "illegal orders" from the military leadership. Gill was charged with treason, which under Pakistani law carries the death penalty. ARY also remains off-air in Pakistan following the broadcast.

Khan has alleged police have abused Gill while in custody. Police say Gill suffers from asthma and has not been abused while detained.

From The Associated Press