Egyptian air strikes destroyed 12 vehicles loaded with arms, ammunition and explosive material trying to cross the border from Libya, the army spokesman said on Tuesday.

The airforce acted after hearing that "criminal elements" had gathered to try and cross the western boundary, the army statement said, without giving details on exactly where or when the strikes took place.

The attacks came a month after Egypt launched a series of air raids in Libya on what it said were Islamist militants responsible for attacking Christians in its territory.

Twenty-nine Coptic Christians were killed in Egypt's southern Minya province in May when masked men attacked their buses as they headed to a monastery. Islamic State claimed responsibility.

Coptic Christians are Egypt's largest minority group and violence against them has increased in recent months.