Lawyers chanted anti-Zardari slogans in many places
Hundreds of lawyers across Pakistan have gone on strike following the dispute between President Asif Ali Zardari and the Supreme Court.
Opposing groups of lawyers, supporting the chief justice and the president, gathered in courts chanting slogans.
The controversy is over the president's attempt to appoint two new judges.
The Supreme Court blocked the attempt saying the president had violated the constitution by not consulting the court about the selections beforehand.
The rift has led to fears that Pakistan could be set for further political instability, correspondents say.
The BBC's M Ilyas Khan in Islamabad says that Pakistan's legal community is divided over the issue.
In some parts of the country groups of lawyers on opposing sides chanted slogans against one another. Minor scuffles between opposing groups were also reported.
Courts were reported to be working across most of Sindh province and in some parts of southern Punjab.
But the strike is being observed more effectively in central Punjab and the North West Frontier Province.
On Saturday, President Asif Ali Zardari issued an order appointing two judges
The Supreme Court later struck the order down, saying it appeared to violate the constitution as the president had not consulted the court about the appointments beforehand.
Mr Zardari's spokesman denied that he had breached the constitution. Farhatullah Babar said the chief justice had been consulted, as required by the constitution.
The Supreme Court will hold a hearing on 18 February.
In December, the Supreme Court threw out an amnesty that protected Mr Zardari from allegations of corruption dating back to the 1980s.
The controversial law granting senior politicians amnesty was brought in by ex-President Pervez Musharraf.
The court's decision in December opened the way to possible prosecution for Mr Zardari's political allies, although he is still protected by presidential immunity.
On Sunday, Prime Minister Yousuf Raza Gilani said there was no link between the appointments and the amnesty ruling.