The right to asylum is enshrined in Article 14 of the Universal Declaration of Human Rights.
The International Convention for the Protection of All Persons from Enforced Disappearance is dealing in Article 16 with a special ban on refoulement:
1. No State Party shall expel, return ("refouler"), surrender or extradite a person to another State where there are substantial grounds for believing that he or she would be in danger of being subjected to enforced disappearance.
2. For the purpose of determining whether there are such grounds, the competent authorities shall take into account all relevant considerations, including, where applicable, the existence in the State concerned of a consistent pattern of gross, flagrant or mass violations of human rights or of serious violations of international humanitarian law.
Refoulement is also banned in Articles 10 and 11 of the African Charter on Human and Peoples' Rights:
1. Every individual shall have the right to free association provided that he abides by the law.
2. Subject to the obligation of solidarity provided for in 29 no one may be compelled to join an association.
Every individual shall have the right to assemble freely with others. The exercise of this right shall be subject only to necessary restrictions provided for by law in particular those enacted in the interest of national security, the safety, health, ethics and rights and freedoms of others.