diff --git a/src/middlewared/middlewared/plugins/alert.py b/src/middlewared/middlewared/plugins/alert.py
index 348b125abb9ab..f8302b7612c81 100644
--- a/src/middlewared/middlewared/plugins/alert.py
+++ b/src/middlewared/middlewared/plugins/alert.py
@@ -26,7 +26,7 @@
     ProThreadedAlertService,
 )
 from middlewared.alert.base import UnavailableException, AlertService as _AlertService
-from middlewared.schema import accepts, Any, Bool, Datetime, Dict, Int, List, Patch, returns, Ref, Str
+from middlewared.schema import accepts, Any, Bool, Datetime, Dict, Int, List, OROperator, Patch, returns, Ref, Str
 from middlewared.service import (
     ConfigService, CRUDService, Service, ValidationErrors,
     job, periodic, private,
@@ -930,34 +930,46 @@ async def oneshot_create(self, job, klass, args):
         await self.middleware.call("alert.send_alerts")
 
     @private
-    @accepts(Str("klass"), Any("query", null=True, default=None))
+    @accepts(
+        OROperator(
+            Str("klass"),
+            List('klass', items=[Str('klassname')], default=None),
+        ),
+        Any("query", null=True, default=None))
     @job(lock="process_alerts", transient=True)
     async def oneshot_delete(self, job, klass, query):
         """
-        Deletes one-shot alerts of specified `klass`, passing `query` to `klass.delete` method.
+        Deletes one-shot alerts of specified `klass` or klasses, passing `query`
+        to `klass.delete` method.
 
         It's not an error if no alerts matching delete `query` exist.
 
-        :param klass: one-shot alert class name (without the `AlertClass` suffix).
+        :param klass: either one-shot alert class name (without the `AlertClass` suffix), or list thereof.
         :param query: `query` that will be passed to `klass.delete` method.
         """
 
-        try:
-            klass = AlertClass.class_by_name[klass]
-        except KeyError:
-            raise CallError(f"Invalid alert source: {klass!r}")
-
-        if not issubclass(klass, OneShotAlertClass):
-            raise CallError(f"Alert class {klass!r} is not a one-shot alert source")
+        if isinstance(klass, list):
+            klasses = klass
+        else:
+            klasses = [klass]
 
-        related_alerts, unrelated_alerts = bisect(lambda a: (a.node, a.klass) == (self.node, klass),
-                                                  self.alerts)
-        left_alerts = await klass(self.middleware).delete(related_alerts, query)
         deleted = False
-        for deleted_alert in related_alerts:
-            if deleted_alert not in left_alerts:
-                self.alerts.remove(deleted_alert)
-                deleted = True
+        for klassname in klasses:
+            try:
+                klass = AlertClass.class_by_name[klassname]
+            except KeyError:
+                raise CallError(f"Invalid alert source: {klassname!r}")
+
+            if not issubclass(klass, OneShotAlertClass):
+                raise CallError(f"Alert class {klassname!r} is not a one-shot alert source")
+
+            related_alerts, unrelated_alerts = bisect(lambda a: (a.node, a.klass) == (self.node, klass),
+                                                      self.alerts)
+            left_alerts = await klass(self.middleware).delete(related_alerts, query)
+            for deleted_alert in related_alerts:
+                if deleted_alert not in left_alerts:
+                    self.alerts.remove(deleted_alert)
+                    deleted = True
 
         if deleted:
             # We need to flush alerts to the database immediately after deleting oneshot alerts.
diff --git a/src/middlewared/middlewared/plugins/ups.py b/src/middlewared/middlewared/plugins/ups.py
index cabb07c10c96f..5e22854288abd 100644
--- a/src/middlewared/middlewared/plugins/ups.py
+++ b/src/middlewared/middlewared/plugins/ups.py
@@ -273,8 +273,8 @@ async def alerts_mapping(self):
 
     @private
     async def dismiss_alerts(self):
-        for alert in (await self.alerts_mapping()).values():
-            await self.middleware.call('alert.oneshot_delete', alert)
+        alerts = list((await self.alerts_mapping()).values())
+        await self.middleware.call('alert.oneshot_delete', alerts)
 
     @private
     @accepts(
diff --git a/tests/api2/test_530_ups.py b/tests/api2/test_530_ups.py
index 5175a14d7156e..765aa064dc0ac 100644
--- a/tests/api2/test_530_ups.py
+++ b/tests/api2/test_530_ups.py
@@ -226,10 +226,11 @@ def test__ups_onbatt_to_online(ups_running, dummy_ups_driver_configured):
 
 def test__ups_online_to_onbatt_lowbattery(ups_running, dummy_ups_driver_configured):
     assert 'UPSOnBattery' not in [alert['klass'] for alert in call('alert.list')]
-    write_fake_data({'battery.charge': 10, 'ups.status': 'OB LB'})
+    write_fake_data({'battery.charge': 90, 'ups.status': 'OB'})
     alert = wait_for_alert('UPSOnBattery')
     assert alert
-    assert 'battery.charge: 10' in alert['formatted'], alert
+    assert 'battery.charge: 90' in alert['formatted'], alert
+    write_fake_data({'battery.charge': 10, 'ups.status': 'OB LB'})
     alert = wait_for_alert('UPSBatteryLow')
     assert alert
     assert 'battery.charge: 10' in alert['formatted'], alert