Theresa May has insisted she will not allow an "industry of vexatious allegations" against British troops over claims of abuse in Iraq.
The Prime Minister said allegations of criminal activity would be investigated properly but steps had been taken to tackle abuse of the system.
She said Britons should be proud of the work done by the armed forces and the disciplined way in which they operate.
The Iraq Historic Allegations Team (IHAT) is looking into claims of murder, abuse and torture carried out by British troops, but the Government-established investigation into claims of abuse linked to the military mission has recently come under fire for its handling of some of the approximately 1,500 allegations it has received.
Concerns have been raised over the "industrial scale" of claims lodged with IHAT supported by the legal aid system.
Mrs May insisted that action had been taken to address false claims and IHAT's work would be completed by the end of 2019, after a review of the system by former director of public prosecutions Sir David Calvert-Smith.
Speaking to reporters travelling with her to New York, Mrs May said: "We should all be proud of our armed forces. Our armed forces do a fantastic job for the United Kingdom in defending the UK, but also in the work that they do around the world in peacekeeping initiatives, on issues like Ebola - the way our armed forces went out and helped there.
"We should be absolutely proud of the fact that we have in our armed forces men and women who are willing to put themselves on the line for our safety and do things that most of us would not contemplate being willing to do in terms of our own safety. They put themselves on the line.
"We can be proud also of the disciplined way in which our armed forces operate.
"But what is important is, if there are allegations - proper allegations - of criminal activity, those need to be investigated.
"But what we do need to make sure is that there isn't an industry of vexatious allegations coming forward. I think measures have been taken.
"The review of IHAT has said that they will be able to focus on cases where there may be questions of allegations which are not the vexatious ones and report within the timescale."