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.

It said that the new requirements were not designed to "prevent or limit" the entry of Sudanese nationals, but rather to stop "illegal activities by individuals and groups on the Sudanese side of the border, who forged entry visas" for profit.

Sudan has been rocked by nearly two months of intense battles between the regular army, led by Abdel Fattah al-Burhan, and the paramilitary Rapid Support Forces (RSF), commanded by Burhan's former deputy Mohamed Hamdan Daglo.

Upwards of 1,800 people have been killed in the fighting, according to the Armed Conflict Location and Event Data Project. Aid agencies and international organisations say the actual toll may be much higher.

The United Nations' International Organization for Migration said nearly two million Sudanese people have been displaced, including 476,000 who have sought refuge in neighbouring countries.

"Egypt has welcomed more than 200,000 Sudanese citizens since the start of the crisis... adding to the approximately five million Sudanese citizens who were already present" in the country before the war, the foreign ministry statement said.

Sudanese media and some social media users have reported over the past two days orders issued by Egyptian authorities at two border crossings with Sudan, according to which "entry into Egypt is allowed only after obtaining a visa, for all age groups and genders".

Egypt's foreign ministry stressed in its statement that its consulates in Sudan have been provided with "the necessary electronic devices to carry out these regulations in a precise, rapid and safe manner, ensuring the orderly entry of Sudanese citizens".