Can't bind to 'disabled' since it isn't a known property of 'a'

Question

<div class="pull-left flex" *ngIf="editBox">
  <input type="text" class="form-control m-t-n-sm" name="panelLabel" [(ngModel)]="agentData.panelLevelAttributes.panelLabel" id="panelLabel" required>
  <a class="btn btn-primary m-t-n-xs btn-sm m-l-sm" [disabled]="panelLabel.invalid"  (click)="updatePanelLabel()">Update</a>
</div>

i am trying this form validation i getting the following error