The three-year-old daughter of a nationalist Assembly member in Northern Ireland was overcome by fumes during an attack on his office today.
Mr Pat Ramsey of the SDLP, a former Mayor of Derry, said two masked youths burst into his office in the city and sprayed an orange substance into the air.
He said the fumes caused his daughter to vomit.
Police said they were investigating the incident, and Mr Ramsay said samples of the substance had been taken away for examination to determine what it was.
"It was horrific for those few moments because I didn't know what it was
and I was quite panicked and anxious for the child and immediately sought medical attention," he said.
There has been an intensive campaign against Mr Ramsey in recent months. Last month a hoax bomb was found in the garden of his home and in February he was the target of another device thrown at a neighbour's house.
He blames dissident republicans for the attacks, and believes it is because he criticised petrol bomb attacks on a Protestant area of the city.
"It is certainly not loyalists who are carrying out these attacks, it's someone from my own community," he said.
Mr Ramsey, leader of the SDLP on Derry City Council, added: "It is appalling in this day and age that people are intent of carrying out this intensive campaign. I have caused no offence or hurt to anyone in my community either by actions or deeds.
"This must stop. These are attacks on democracy not on Pat Ramsey."
PA