Very likely fungus gnats, which can be an issue with many houseplants. Typically they are attracted to damp, organic soils, where the adult gnats lay eggs that develop into larvae that feeds on the soil organic material and plant roots.

Fungus gnats are usually a sign of overwatering. Or a potting mix that is excessively water retentive. Cutting back on the watering or repotting with a fresh, better draining soil mix is advised.

You can trap the adult gnats with yellow sticky traps and kill the larvae by dosing with a dilute hydrogen peroxide solution. But they will return if you do not address the soil or watering issues as well.

I put the yellow sticky strips (sold as whitefly traps) flat on the windowsills and around the plant tables. It's amazing what you catch! Also, let the soil surfaces dry out before watering.

Not to pick, but saying “let the soil surface dry out before watering” can lead people down the wrong path.

When you water when only the surface is dry, it could be soggy lower in the pot.

Yes, I gave general advice. The gnats like damp surfaces in which to lay eggs. I know there's so much more to soil science.