Police have taken former Pakistani military ruler Pervez Musharraf into custody at their Islamabad headquarters.
Mohammed Amjad, a spokesman for Musharraf, said the ex-general will spend two days in a police guest house ahead of a hearing at an antiterrorism court.
Amjad said police took custody of Musharraf on April 19 after a senior official failed to issue paperwork implementing a judge's order to detain him at his home.
Musharraf's lawyers said they will appeal the arrest in the Supreme Court.
The ex-general posted a message on his Facebook page, calling his arrest an "unwarranted act of the Islamabad High Court." He called the charges "politically motivated."
A judge in the Islamabad High Court revoked Musharraf's bail and issued an arrest order on April 18, but he fled the court.
Musharraf, 69, is facing charges in connection with the firing of senior judges in 2007, when he imposed emergency rule and suspended the constitution.
After he left the court on April 18, the Islamabad court added a terrorism charge in connection with Musharraf's dismissal of the judges.
Musharraf returned to Pakistan in March after four years of self-imposed exile. He planned to run in the May 11 general elections, but he has been disqualified.
Courts and election officials across the country barred his candidacy in his four chosen constituencies.
'I Helped Pakistan'
In a video statement late on April 18, Musharraf characterized his arrest orders and the litany of court cases as an attempt to force him out of politics.
"Why I am being stopped from participating in politics in Pakistan? Is this because I helped Pakistan to develop and enhanced its security? Or because I gave Pakistani people prosperity and their rights?" he asked.
Musharraf, who ruled the country for nearly nine years after a military coup in October 1999, went on to list his achievements.
"I help build a lot of roads and dams. I promoted telecommunication and information technology and vastly enhanced Pakistan's defense capabilities and made it very strong," the former general said.
"I brought an industrial and agricultural revolution and helped the country's economy propel to the top 11 global economies."
Before returning, Musharraf was also granted bail in cases related to the 2007 killings of former Prime Minister Benazir Bhutto and a Baluch rebel leader in 2006.
With reporting by Reuters and AP