How to set updateprogress when clicking on button inside the update panel?

<asp:ScriptManager ID="ScriptManager1" runat="server" EnablePartialRendering="true">
        </asp:ScriptManager>
        <asp:UpdatePanel runat="server" ID="UpdatePanel1">
            <ContentTemplate>
                <asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click" />
            </ContentTemplate>
        </asp:UpdatePanel>
        <asp:UpdateProgress runat="server" ID="PageUpdateProgress" AssociatedUpdatePanelID="Panel" >
            <ProgressTemplate>
                Please wait til the operation completes
                <%--You can add your loading image here--%>
                <img alt="progress" src="images/loading.gif" />
            </ProgressTemplate>
        </asp:UpdateProgress>
        <asp:UpdatePanel runat="server" ID="Panel">
            <ContentTemplate>
                <asp:Button runat="server" ID="UpdateButton" OnClick="UpdateButton_Click" Text="Update" />
            </ContentTemplate>
        </asp:UpdatePanel>

protected void Button1_Click(object sender, EventArgs e)
        {
            System.Threading.Thread.Sleep(5000);
        }


        protected void UpdateButton_Click(object sender, EventArgs e)
        {
            System.Threading.Thread.Sleep(5000);
        }

Thanks,
A2H
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