diff --git a/packages/gantt/src/i18n/i18n.ts b/packages/gantt/src/i18n/i18n.ts
index 6db24e52..8b26e134 100644
--- a/packages/gantt/src/i18n/i18n.ts
+++ b/packages/gantt/src/i18n/i18n.ts
@@ -1,5 +1,5 @@
 import { InjectionToken } from '@angular/core';
-import { Locale as DateFnsLocale } from 'date-fns';
+import type { Locale as DateFnsLocale } from 'date-fns';
 import { GanttViewType } from '../class';
 
 export enum GanttI18nLocale {
diff --git a/packages/gantt/src/i18n/locales/de-de.ts b/packages/gantt/src/i18n/locales/de-de.ts
index 3b5294a0..5924aa5b 100644
--- a/packages/gantt/src/i18n/locales/de-de.ts
+++ b/packages/gantt/src/i18n/locales/de-de.ts
@@ -1,10 +1,11 @@
 import { de } from 'date-fns/locale';
+import type { Locale as DateFnsLocale } from 'date-fns';
 import { GanttViewType } from '../../class';
 import { GanttI18nLocale } from '../i18n';
 
 export default {
     id: GanttI18nLocale.deDe,
-    dateLocale: de,
+    dateLocale: de as DateFnsLocale,
     views: {
         [GanttViewType.hour]: {
             label: 'Stündlich',
diff --git a/packages/gantt/src/i18n/locales/ru-ru.ts b/packages/gantt/src/i18n/locales/ru-ru.ts
index 0eea054d..ef3a798b 100644
--- a/packages/gantt/src/i18n/locales/ru-ru.ts
+++ b/packages/gantt/src/i18n/locales/ru-ru.ts
@@ -1,10 +1,11 @@
 import { ru } from 'date-fns/locale';
+import type { Locale as DateFnsLocale } from 'date-fns';
 import { GanttViewType } from '../../class';
 import { GanttI18nLocale } from '../i18n';
 
 export default {
     id: GanttI18nLocale.ruRu,
-    dateLocale: ru,
+    dateLocale: ru as DateFnsLocale,
     views: {
         [GanttViewType.hour]: {
             label: 'Ежечасно',
diff --git a/packages/gantt/src/utils/date.ts b/packages/gantt/src/utils/date.ts
index b4d908b5..d890cf01 100644
--- a/packages/gantt/src/utils/date.ts
+++ b/packages/gantt/src/utils/date.ts
@@ -30,10 +30,9 @@ import {
     startOfHour,
     endOfHour,
     endOfMinute,
-    Locale,
-    FirstWeekContainsDate
+    Locale
 } from 'date-fns';
-
+import type { FirstWeekContainsDate } from 'date-fns/types';
 import { TZDate } from '@date-fns/tz';
 
 export {