The Police Service of Northern Ireland said warning telephone calls were received at about 7:30 p.m., a half hour before the explosions, CNN reported. Parts of the city center were evacuated and no injuries were reported.
Londonderry, called Derry by nationalists, has an overwhelmingly Catholic population. The city is to be the first British City of Culture in 2013, and dissident Republicans have bombed the program's offices.
Officials on both sides of the sectarian divide condemned the bombing.
"This was an attack on the people of Derry by the enemies of Ireland," said Colum Eastwood, the nationalist mayor. "Those behind this are engaged in a futile and morally bankrupt campaign."
Tom Elliott, the head of the Ulster Unionist Party, said the city became used to bombing during the Troubles of the 1970s and 1980s.
"Those attacks failed to break the will of the unionist people and these attacks will fail, too," he said. "These attacks further no cause."
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