Despite repeated pledges from both sides, fighting has flared this week both in greater Khartoum and in the western region of Darfur.
The Patriotic Bill prohibits citizens from holding meetings with foreign governments.
The United States said there had been "serious violations of the ceasefire by both sides".
Zimbabwe President Emmerson Mnangagwa has finally set August 23 as the long-awaited election date.
An anonymous Sudanese state official said RSF had repeatedly violated the truce.