Egypt has announced that as of Saturday it requires all citizens of neighbouring Sudan, engulfed in bloody conflict since mid-April, to obtain a visa before they can cross the border.

Since fighting broke out between two rival generals vying for control in Sudan, some 200,000 Sudanese nationals have entered Egypt, most of them through land crossings, Cairo said.

Egyptian authorities had so far exempted Sudanese women of all ages, children under 16 and anyone over 50 from having to obtain a visa prior to arrival at a point of entry.

Cairo's foreign ministry issued a statement on Saturday announcing the new regulations, justifying the move as a crackdown on "illegal activities" including fraud.

The authorities introduced visa procedures aimed at regulating "the entry of the brotherly Sudanese (people) into Egypt after more than 50 days of crisis" in their country, the statement said.