diff --git a/Lib/datetime.py b/Lib/datetime.py
@@ -857,7 +857,7 @@ def fromisoformat(cls, date_string):
            assert len(date_string) == 10
            return cls(*_parse_isoformat_date(date_string))
        except Exception:
-            raise ValueError('Invalid isoformat string: %s' % date_string)


    # Conversions to string
@@ -1369,7 +1369,7 @@ def fromisoformat(cls, time_string):
        try:
            return cls(*_parse_isoformat_time(time_string))
        except Exception:
-            raise ValueError('Invalid isoformat string: %s' % time_string)


    def strftime(self, fmt):
@@ -1646,13 +1646,13 @@ def fromisoformat(cls, date_string):
        try:
            date_components = _parse_isoformat_date(dstr)
        except ValueError:
-            raise ValueError('Invalid isoformat string: %s' % date_string)

        if tstr:
            try:
                time_components = _parse_isoformat_time(tstr)
            except ValueError:
-                raise ValueError('Invalid isoformat string: %s' % date_string)
        else:
            time_components = [0, 0, 0, 0, None]


diff --git a/Lib/test/datetimetester.py b/Lib/test/datetimetester.py
@@ -13,6 +13,7 @@
import os
import pickle
import random
import struct
import unittest

@@ -2676,6 +2677,14 @@ def test_fromisoformat_fails_datetime(self):
                with self.assertRaises(ValueError):
                    self.theclass.fromisoformat(bad_str)

    def test_fromisoformat_utc(self):
        dt_str = '2014-04-19T13:21:13+00:00'
        dt = self.theclass.fromisoformat(dt_str)