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We present spatially resolved ALMA images of CO J=3-2 emission from theprotoplanetary disk around HD100546. We model the spatially-resolved kinematicstructure of the CO emission. Assuming a velocity profile which prescribes aflat or flared emitting surface in Keplerian rotation, we uncover significantresiduals with a peak of $\approx7\delta v$, where $\delta v = 0.21$ kms$^{-1}$ is the width of a spectral resolution element. The residuals revealthe possible presence of a severely warped and twisted inner disk extending toat most 100au. Adapting the model to include a misaligned inner gas disk with(i) an inclination almost edge-on to the line of sight, and (ii) a positionangle almost orthogonal to that of the outer disk reduces the residuals to $<3\delta v$. However, these findings are contrasted by recent VLT/SPHERE,MagAO/GPI, and VLTI/PIONIER observations of HD100546 that show no evidence of aseverely misaligned inner dust disk down to spatial scales of $\sim 1$au. Analternative explanation for the observed kinematics are fast radial flowsmediated by (proto)planets. Inclusion of a radial velocity component at closeto free-fall speeds and inwards of $\approx 50$au results in residuals of$\approx 4 \delta v$. Hence, the model including a radial velocity componentonly does not reproduce the data as well as that including a twisted andmisaligned inner gas disk. Molecular emission data at a higher spatialresolution (of order 10au) are required to further constrain the kinematicswithin $\lesssim 100$au. HD100546 joins several other protoplanetary disks forwhich high spectral resolution molecular emission shows that the gas velocitystructure cannot be described by a purely Keplerian velocity profile with auniversal inclination and position angle. Regardless of the process, the mostlikely cause is the presence of an unseen planetary companion. (Abridged)

CO emission tracing a warp or radial flow within $\lesssim$ 100 au in the HD 100546 protoplanetary disk