Egypt's Interior Ministry says the death toll from a mortar attack on a checkpoint near northern Sinai's provincial capital of el-Arish has risen to 15 policemen killed.

The ministry says in a Sunday statement that the dead include three officers.

A Sinai-based Islamic State affiliate has claimed responsibility for the Saturday attack, according to a statement circulated on social media. The Associated Press could not independently verify the claim.

The IS affiliate has claimed responsibility for most of the attacks against Egyptian security forces, which have intensified since the July 2013 military ouster of Islamist President Mohammed Morsi.

While the attacks have largely taken place in northern Sinai, they have also hit other areas including the capital, Cairo.