Complex sentence: During the night, the Menagh air base had been reportedly captured by the SDF, however, this was denied by the pro-opposition activist group the SOHR, as fighting was still taking place in the Menagh area and at the air base.
Split into simpler sentences: During the night, the Menagh air base had been reportedly captured by the SDF. The following day, the seizure of the military airport was denied by the pro-opposition activist group the SOHR, as fighting was still taking place in the Menagh area and at the air base.