diff --git a/src/Model/Group.php b/src/Model/Group.php
index 58c59268e7..fa41d26467 100644
--- a/src/Model/Group.php
+++ b/src/Model/Group.php
@@ -310,6 +310,68 @@ class Group
 		return DBA::delete('group_member', ['gid' => $gid, 'contact-id' => $cid]);
 	}
 
+	/**
+	 * Adds contacts to a group
+	 *
+	 * @param int $gid
+	 * @param array $contacts
+	 * @throws \Exception
+	 */
+	public static function addMembers(int $gid, array $contacts)
+	{
+		if (!$gid || !$contacts) {
+			return false;
+		}
+
+		// @TODO Backward compatibility with user contacts, remove by version 2022.03
+		$group = DBA::selectFirst('group', ['uid'], ['id' => $gid]);
+		if (empty($group)) {
+			throw new HTTPException\NotFoundException('Group not found.');
+		}
+
+		foreach ($contacts as $cid) {
+			$cdata = Contact::getPublicAndUserContactID($cid, $group['uid']);
+			if (empty($cdata['user'])) {
+				throw new HTTPException\NotFoundException('Invalid contact.');
+			}
+
+			DBA::insert('group_member', ['gid' => $gid, 'contact-id' => $cdata['user']], Database::INSERT_IGNORE);
+		}
+	}
+
+	/**
+	 * Removes contacts from a group
+	 *
+	 * @param int $gid
+	 * @param array $contacts
+	 * @throws \Exception
+	 */
+	public static function removeMembers(int $gid, array $contacts)
+	{
+		if (!$gid || !$contacts) {
+			return false;
+		}
+
+		// @TODO Backward compatibility with user contacts, remove by version 2022.03
+		$group = DBA::selectFirst('group', ['uid'], ['id' => $gid]);
+		if (empty($group)) {
+			throw new HTTPException\NotFoundException('Group not found.');
+		}
+
+		$contactIds = [];
+
+		foreach ($contacts as $cid) {
+			$cdata = Contact::getPublicAndUserContactID($cid, $group['uid']);
+			if (empty($cdata['user'])) {
+				throw new HTTPException\NotFoundException('Invalid contact.');
+			}
+
+			$contactIds[] = $cdata['user'];
+		}
+
+		DBA::delete('group_member', ['gid' => $gid, 'contact-id' => $contactIds]);
+	}
+
 	/**
 	 * Returns the combined list of contact ids from a group id list
 	 *
diff --git a/src/Module/Api/Mastodon/Lists/Accounts.php b/src/Module/Api/Mastodon/Lists/Accounts.php
index 6dcde12b7d..413cacae29 100644
--- a/src/Module/Api/Mastodon/Lists/Accounts.php
+++ b/src/Module/Api/Mastodon/Lists/Accounts.php
@@ -36,12 +36,32 @@ class Accounts extends BaseApi
 {
 	protected function delete(array $request = [])
 	{
-		$this->response->unsupported(Router::DELETE, $request);
+		self::checkAllowedScope(self::SCOPE_WRITE);
+
+		$request = $this->getRequest([
+			'account_ids' => [], // Array of account IDs to remove from the list
+		], $request);
+
+		if (empty($request['account_ids']) || empty($this->parameters['id'])) {
+			DI::mstdnError()->UnprocessableEntity();
+		}
+
+		return Group::removeMembers($this->parameters['id'], $request['account_ids']);
 	}
 
 	protected function post(array $request = [])
 	{
-		$this->response->unsupported(Router::POST, $request);
+		self::checkAllowedScope(self::SCOPE_WRITE);
+
+		$request = $this->getRequest([
+			'account_ids' =>  [], // Array of account IDs to add to the list
+		], $request);
+
+		if (empty($request['account_ids']) || empty($this->parameters['id'])) {
+			DI::mstdnError()->UnprocessableEntity();
+		}
+
+		return Group::addMembers($this->parameters['id'], $request['account_ids']);
 	}
 
 	/**