Pakistan's top security official warned opposition leader Nawaz Sharif on Monday that his recent anti-government speeches amount to treason.

Rehman Malik said the government had "no intention" of arresting Sharif but suggested it had the grounds to do so.

Political tensions are rising in Pakistan ahead of a planned anti-government rally in the capital by Sharif's party and lawyers later this week. The crisis comes as the nuclear-armed country battles rising violence by al-Qaida and Taliban militants.

In a televised media conference, Malik read out extracts from several speeches he said were made by Sharif, a former prime minister, in recent weeks.

"Inciting people for disobedience is sedition. ... It could get life imprisonment and a fine," Malik said.

Any move to arrest Sharif or other high-profile members of his party would be a major escalation of the crisis and would likely trigger violent protests.

Rehman also appealed for Sharif to negotiate with the government for a solution to the crisis, which was triggered last month when the Supreme Court banned the opposition leader and his brother from elected office.

Malik said the government would not outlaw the march but said the protesters would not be allowed to rally in front of the parliament building or other downtown areas, as they are planning. He suggested they protest in a park on the outskirts of the Islamabad.