“We cannot ignore Hiroshima and Nagasaki, with the useless use of nuclear weapons, an absolutely unnecessary use that, in any case, could have been employed against some military facilities that fell, however, on civilian populations of hundreds of thousands of inhabitants, to establish the era of the atomic terror in the world.”

Report on the Potsdam Conference (1945)
Context: The world will note that the first atomic bomb was dropped on Hiroshima, a military base. That was because we wished in this first attack to avoid, insofar as possible, the killing of civilians. But that attack is only a warning of things to come. If Japan does not surrender, bombs will have to be dropped on her war industries and, unfortunately, thousands of civilian lives will be lost. I urge Japanese civilians to leave industrial cities immediately, and save themselves from destruction.

2012

Time (8 June 1981) " An Interview with Gaddafi http://www.time.com/time/magazine/article/0,9171,922551-2,00.html"
Interviews

Nobel Prize lecture (2005)

1960s, Beyond Vietnam: A Time to Break Silence (1967)
Context: War is not the answer. Communism will never be defeated by the use of atomic bombs or nuclear weapons. Let us not join those who shout war and, through their misguided passions, urge the United States to relinquish its participation in the United Nations. These are days which demand wise restraint and calm reasonableness. We must not engage in a negative anticommunism, but rather in a positive thrust for democracy, realizing that our greatest defense against communism is to take offensive action in behalf of justice. We must with positive action seek to remove those conditions of poverty, insecurity, and injustice, which are the fertile soil in which the seed of communism grows and develops.

Hansard http://www.parliament.the-stationery-office.co.uk/pa/cm200102/cmhansrd/vo020924/debtext/20924-01.htm#20924-01_spmin0 House of Commons, 6th series, vol. 390, col. 3.
House of Commons statement on publication of the dossier concerning Iraq and Weapons of Mass Destruction, 24 September 2002.
2000s

On potentials for misuse of nuclear power, p. 31
Portraits in Science interviews (1994)
Context: I, who had been in favour of nuclear energy for generating electricity … I suddenly realised that anybody who has a nuclear reactor can extract the plutonium from the reactor and make nuclear weapons, so that a country which has a nuclear reactor can, at any moment that it wants to, become a nuclear weapons power. And I, right from the beginning, have been terribly worried by the existence of nuclear weapons and very much against their use.

The London Standard (30 September 1986).
1980s

Quoted in CornwallLive. Cornwall and Devon European MP Molly Scott Cato arrested after breaking into US air base in Belgium https://www.cornwalllive.com/news/cornwall-news/cornwall-devon-european-mp-molly-2564421 (20 February 2019)
2019