diff --git a/abstract/ActivityBlock.js b/abstract/ActivityBlock.js
index 6878ed45e..36b8eda83 100644
--- a/abstract/ActivityBlock.js
+++ b/abstract/ActivityBlock.js
@@ -144,6 +144,7 @@ export class ActivityBlock extends Block {
 
     if (!hasCurrentActivityInCtx) {
       this.$['*currentActivity'] = null;
+      this.setOrAddState('*modalActive', false);
     }
   }
 
@@ -199,4 +200,4 @@ ActivityBlock.activities = Object.freeze({
   DETAILS: 'details',
 });
 
-/** @typedef {(typeof ActivityBlock)['activities'][keyof (typeof ActivityBlock)['activities']] | null} ActivityType */
+/** @typedef {(typeof ActivityBlock)['activities'][keyof (typeof ActivityBlock)['activities']] | (string & {}) | null} ActivityType */
diff --git a/abstract/Block.js b/abstract/Block.js
index f4e68c554..ba4b27182 100644
--- a/abstract/Block.js
+++ b/abstract/Block.js
@@ -118,15 +118,6 @@ export class Block extends BaseComponent {
     );
   }
 
-  /** @param {import('./ActivityBlock.js').ActivityType} activityType */
-  setActivity(activityType) {
-    if (this.hasBlockInCtx((b) => b.activityType === activityType)) {
-      this.$['*currentActivity'] = activityType;
-      return;
-    }
-    console.warn(`Activity type "${activityType}" not found in the context`);
-  }
-
   connectedCallback() {
     const styleAttrs = /** @type {typeof Block} */ (this.constructor).styleAttrs;
     styleAttrs.forEach((attr) => {
diff --git a/abstract/CTX.js b/abstract/CTX.js
index 92d88c7d3..4462de40b 100644
--- a/abstract/CTX.js
+++ b/abstract/CTX.js
@@ -6,14 +6,14 @@ export const blockCtx = () => ({});
 /** @param {import('./Block').Block} fnCtx */
 export const activityBlockCtx = (fnCtx) => ({
   ...blockCtx(),
-  '*currentActivity': '',
+  '*currentActivity': null,
   '*currentActivityParams': {},
   '*history': [],
   '*historyBack': null,
   '*closeModal': () => {
     fnCtx.set$({
+      '*currentActivity': null,
       '*modalActive': false,
-      '*currentActivity': '',
     });
   },
 });
diff --git a/abstract/UploaderBlock.js b/abstract/UploaderBlock.js
index b704cfb96..98e106a3f 100644
--- a/abstract/UploaderBlock.js
+++ b/abstract/UploaderBlock.js
@@ -107,6 +107,14 @@ export class UploaderBlock extends ActivityBlock {
     if (!this.$['*secureUploadsManager']) {
       this.$['*secureUploadsManager'] = new SecureUploadsManager(this);
     }
+
+    if (this.has('*modalActive')) {
+      this.sub('*modalActive', (modalActive) => {
+        if (modalActive && !this.$['*currentActivity']) {
+          this.$['*modalActive'] = false;
+        }
+      });
+    }
   }
 
   /** @type {string[]} */
diff --git a/abstract/UploaderPublicApi.js b/abstract/UploaderPublicApi.js
index fd17a3261..7373f11bb 100644
--- a/abstract/UploaderPublicApi.js
+++ b/abstract/UploaderPublicApi.js
@@ -275,4 +275,28 @@ export class UploaderPublicApi {
       this._ctx.setOrAddState('*modalActive', false);
     }
   }
+
+  /**
+   * @param {import('./ActivityBlock.js').ActivityType} activityType
+   * @param {import('../blocks/ExternalSource/ExternalSource.js').ActivityParams | {}} [params]
+   */
+  setCurrentActivity(activityType, params = {}) {
+    if (this._ctx.hasBlockInCtx((b) => b.activityType === activityType)) {
+      this._ctx.set$({
+        '*currentActivityParams': params,
+        '*currentActivity': activityType,
+      });
+      return;
+    }
+    console.warn(`Activity type "${activityType}" not found in the context`);
+  }
+
+  /** @param {boolean} active */
+  setModalActive(active) {
+    if (active && !this._ctx.$['*currentActivity']) {
+      console.warn(`Can't open modal without current activity. Please use "setCurrentActivity" method first.`);
+      return;
+    }
+    this._ctx.setOrAddState('*modalActive', active);
+  }
 }
diff --git a/blocks/ExternalSource/ExternalSource.js b/blocks/ExternalSource/ExternalSource.js
index ec7282424..87c7e417d 100644
--- a/blocks/ExternalSource/ExternalSource.js
+++ b/blocks/ExternalSource/ExternalSource.js
@@ -72,6 +72,13 @@ export class ExternalSource extends UploaderBlock {
       onActivate: () => {
         let { externalSourceType } = /** @type {ActivityParams} */ (this.activityParams);
 
+        if (!externalSourceType) {
+          this.$['*currentActivity'] = null;
+          this.setOrAddState('*modalActive', false);
+          console.error(`Param "externalSourceType" is required for activity "${this.activityType}"`);
+          return;
+        }
+
         this.set$({
           activityCaption: `${externalSourceType?.[0].toUpperCase()}${externalSourceType?.slice(1)}`,
           activityIcon: externalSourceType,
@@ -80,6 +87,13 @@ export class ExternalSource extends UploaderBlock {
         this.mountIframe();
       },
     });
+    this.sub('*currentActivityParams', (val) => {
+      if (!this.isActivityActive) {
+        return;
+      }
+      this.unmountIframe();
+      this.mountIframe();
+    });
     this.sub('*currentActivity', (val) => {
       if (val !== this.activityType) {
         this.unmountIframe();
diff --git a/types/exported.d.ts b/types/exported.d.ts
index ba034a1d6..5ea490df0 100644
--- a/types/exported.d.ts
+++ b/types/exported.d.ts
@@ -3,6 +3,7 @@ import type { complexConfigKeys } from '../blocks/Config/Config';
 import type { FuncFileValidator, FuncCollectionValidator } from '../abstract/ValidationManager';
 
 export type { FuncFileValidator, FuncCollectionValidator } from '../abstract/ValidationManager';
+export type { UploaderPublicApi } from '../abstract/UploaderPublicApi';
 
 export type UploadError = import('@uploadcare/upload-client').UploadError;
 export type UploadcareFile = import('@uploadcare/upload-client').UploadcareFile;
diff --git a/types/test/lr-upload-ctx-provider.test-d.tsx b/types/test/lr-upload-ctx-provider.test-d.tsx
index ed461bc57..f6d0d0335 100644
--- a/types/test/lr-upload-ctx-provider.test-d.tsx
+++ b/types/test/lr-upload-ctx-provider.test-d.tsx
@@ -14,11 +14,12 @@ import { useRef } from 'react';
 import { UploadcareFile, UploadcareGroup } from '@uploadcare/upload-client';
 
 const instance = new UploadCtxProvider();
-
-instance.api.addFileFromUrl('https://example.com/image.png');
 instance.uploadCollection.size;
 instance.setOrAddState('fileId', 'uploading');
 
+const api = instance.api;
+api.addFileFromUrl('https://example.com/image.png');
+
 instance.addEventListener('change', (e) => {
   expectType<EventMap['change']>(e);
 });
@@ -42,7 +43,7 @@ instance.addEventListener('change', (e) => {
     expectType<false>(state.isFailed);
     expectType<false>(state.isUploading);
     expectType<[]>(state.errors);
-    expectType<'success'>(state.allEntries[0].status)
+    expectType<'success'>(state.allEntries[0].status);
   } else if (state.isFailed) {
     expectType<'failed'>(state.status);
     expectType<false>(state.isSuccess);
@@ -61,7 +62,7 @@ instance.addEventListener('change', (e) => {
     expectType<false>(state.isFailed);
     expectType<false>(state.isUploading);
     expectType<[]>(state.errors);
-    expectType<'success' | 'idle'>(state.allEntries[0].status)
+    expectType<'success' | 'idle'>(state.allEntries[0].status);
   }
 });
 
@@ -204,7 +205,9 @@ instance.addEventListener('modal-open', (e) => {
 
 instance.addEventListener('activity-change', (e) => {
   const payload = e.detail;
-  expectType<(typeof ActivityBlock)['activities'][keyof (typeof ActivityBlock)['activities']] | null>(payload.activity);
+  expectType<(typeof ActivityBlock)['activities'][keyof (typeof ActivityBlock)['activities']] | null | (string & {})>(
+    payload.activity,
+  );
 });
 
 () => {