Metropolitan police have said the graffiti on the RAF Bomber Command War Memorial and the Animals in War Memorial in central London is being treated as criminal damage.
In a statement, they said:
At 5am this morning police discovered graffiti on both the RAF Bomber Command War Memorial in Green Park and the Animals in War Memorial on Park Lane.
Royal Parks' officers and Westminster police are investigating.
There have been no arrests at present.
More top news
Tougher regulations coming into effect today are intended to crack down on motorists driving under the influence of drugs.
A Finnish punk band whose members have autism and Down's Syndrome have been chosen as the country's entry for the Eurovision Song Contest.
The PM promises to double to 200,000 the number of homes built under an existing scheme aimed at easing Britain's housing shortage.