STOCKHOLM, Feb 7 (Reuters) - Securitas, the world's second-biggest listed security services group, reported on Wednesday a rise in core profit that slightly lagged expectation, and said profitability ­was dragged down with poor results in its Critical infrastructure services.

Operating profit before amortisation (EBITA) at the Swedish company rose to 2.68 billion Swedish crowns ($255.70 million)from a year-ago 2.49 billion.

This was against an average analyst forecast of 2.75 billion in a poll provided by the company.

(Reporting by Marie Mannes, editing by Essi Lehto)