Any foreign person who intends to enter El Salvador must comply with the following requirements
following requirements:

• Present a valid passport or valid travel document, in good condition.
• Carry the valid visa or special permit in good condition, when applicable.
• Not be subject to the entry impediment established in article 40 of this law.
• Comply with the procedures in force in the migratory delegations and other requirements established in the Regulations of this Law.

Exceptionally, when there are humanitarian reasons, public interest or fulfillment of commitments acquired by the State of El Salvador commitments acquired by the State of El Salvador, it will be possible to authorize the entrance of foreign persons who do not foreigners who do not meet the aforementioned requirements; by means of a duly motivated resolution issued by the General reasoned resolution issued by the General Directorate. 

Additional:

• Instruction f-15 is directed to Foreign persons such as:

1. Who for humanitarian reasons justify to the General Directorate a special treatment. Art. 109 paragraph 20) of the Special Law on Migration and Aliens.
2. That as a result of the process to recognize the refugee status does not meet the requirements to be recognized as such. Art. 109 paragraph 21) of the Special Law on Migration and Aliens.
3. That, for reasons of collaboration with the justice system under the regime of protection of victims, witnesses, experts or subjects of judicial process. Art. 109 paragraph 22) of the Special Immigration and Alien Law.

For the management of Temporary Residence for Humanitarian Reasons, Complementary Protection, Residents who collaborate with justice.

Important:

The waiting time for a response is thirty (30) working days, as long as the requirements are met.

More information here.