Grinding noise from the timing belt

I have relatively little knowledge of inner workings of a civic engine, but today I started hearing a grinding/rattling noise under the hood. I checked where the noise was coming from, and it seems to be coming from the timing belt area, rather where the main pulley is located. The belts are in good shape and are not loose in any way. Does anyone know what this may be? Is it the pulley's bearings that might have gotten damaged or something else? It's definitely not coming from the engine part (i.e. top of the engine), so I suppose the valves are OK. I read some articles online and a few of them say that a power steering pump can have a grinding noise as well, but based on where this noise is coming from, it sounds like it is coming straight from the main pulley...

Any ideas?

Thanks,

[Honda Civic 2002 - LS]