Northern Ireland's troubled past should be addressed fairly and proportionately, the Prime Minister said.
Theresa May defended the independence of prosecutors considering charging 18 British soldiers over involvement in the Bloody Sunday shootings in Londonderry.
Thirteen people died when members of the Parachute Regiment opened fire on civil rights demonstrators in 1972. A 14th person died later.
Mrs May said: "First of all prosecutors are independent and they will make their decisions, rightly, absolutely independently.
"I think what is important as we look forward is that as we see, looking into those issues of legacy and looking into what has happened in the past, that we ensure that is done in a fair and proportionate way."
The Prime Minister visited an agricultural show near Belfast on Saturday as part of the General Election campaign.
All those killed on Bloody Sunday were later pronounced innocent by a public inquiry led by Lord Saville, and then-prime minister David Cameron said the killings were unjustified and unjustifiable.
Prosecution of soldiers from Northern Ireland's 30-year conflict has attracted criticism in some quarters from those opposed to dragging elderly ex-servicemen through the courts.
Earlier this year a pro-military rally was organised by Justice For Northern Ireland Veterans (JFNIV) to highlight what it alleges is a legal witch-hunt against former security members who served during the Troubles.
The campaign group, which formed in response to a number of recent prosecutions of former soldiers in relation to incidents during the region's sectarian conflict, held similar rallies in London and Glasgow.
Prosecutors in Northern Ireland have pursued five times more prosecutions against alleged paramilitaries than soldiers in the last five years, the Public Prosecution Service (PPS) has disclosed.
One third of cases which the director of public prosecutions has referred to police to investigate relate to Troubles incidents involving security force members.