A senior Muslim Brotherhood leader has written an open letter from exile to a retired Egyptian army general seeking to run for president, listing the outlawed group's conditions for supporting his candidacy.

Youssef Nada's letter was posted on his Facebook account on Monday.

The letter has provided media loyal to President Abdel-Fattah el-Sissi with ammunition to link the would-be candidate, former chief of staff Sami Annan, to the banned Brotherhood. Authorities accuse the group of taking up arms against the government.

El-Sissi led the military's 2013 ouster of former president Mohammed Morsi, an Islamist and Brotherhood stalwart. Under el-Sissi, links to the Brotherhood are grounds for prosecution.

Nada cited the demand to free Morsi, in jail since 2013, as one of the Brotherhood's conditions for supporting Annan.