Draped in a South African flag, the coffin of Nelson Mandela arrived on Wednesday at the colonnaded Union Buildings, the seat of official power overlooking the capital, where the body will lie in state for three days before his funeral on Sunday.

A day after tens of thousands of South Africans joined world leaders including President Obama at a national memorial in Soweto, the cortege’s journey from a military mortuary marked the latest moment of national mourning since Mr. Mandela died on Thursday at age 95. He was celebrated on Tuesday by Mr. Obama as the last great liberator of the 20th century.

In the esplanade of the Union Buildings, a military honor guard formed up as the coffin arrived under bright skies — a marked contrast with the rain that drenched Tuesday’s ceremony in Soweto. Mandla Mandela, Mr. Mandela’s grandson, led family mourners as a military band played the national anthem, Nkosi Sikelele Afrika, or God Bless Africa.

A phalanx of police motorcycles had escorted the black hearse carrying the coffin past knots of well-wishers on the streets of Pretoria. The authorities had urged South Africans to form a “people’s” honor guard along the route of the cortege.

Hundreds of people joined equal numbers of police officers and members of the army to watch the coffin pass. The lying-in-state is to be tightly controlled, with mourners shuttled in from assembly points. Many streets in the capital were closed to normal traffic as the cortege passed by.

The coffin is to be transported each day for three days to the sandstone Union Buildings before the body is flown to the Eastern Cape for the state funeral in Mr. Mandela’s childhood home of Qunu.

Some watched the coffin pass with heads bowed, others raised their fists in the militant salute Mr. Mandela favored. At the corner of Steve Biko Street and Madiba Avenue, women gathered to sing his praises and wait for Mr. Mandela’s body to return to the spot where he was sworn in as South Africa’s first black president in 1994.

The Union Buildings lie on the highest point of the hills above Pretoria. The edifice was designed by Sir Herbert Baker in 1908 and building was completed in 1913 as the central administrative headquarters of the Union of South Africa, the forerunner of the Republic of South Africa created in 1961.

The building, with its sweeping, winged facade dominating the leafy bowl of the capital below, has been the seat of power since it was built, an emblem of white authority until the country’s first democratic elections brought Mr. Mandela to power in 1994.

The coffin was placed on Wednesday on a catafalque below on impromptu shelter in the Union Buildings’ amphitheater.

Lydia Polgreen and nicholas Kulish reported from Pretoria, South Africa, and Alan Cowell from London