Nuget does not import .targets

I want to add my .targets file into project via nuget.I have next .nuspec file:

<package ><metadata>  ...</metadata><files><file src="..\..\Rcs\Rcs\bin\Release\Rcs.targets" target="build\Rcs.targets" /><file src="..\..\Rcs\Rcs\bin\Release\Rcs.dll" target="lib\Xamarin.iOS10\Rcs.dll" />     <file src="..\..\Rcs\Rcs\bin\Release\*.dll" /><file src="..\..\Rcs\Rcs\bin\Release\*.config" /></files></package>

And .targets file:

<?xml version="1.0" encoding="utf-8"?><Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003"><PropertyGroup><RcsDirectory Condition="$(RcsDirectory) == '' Or $(RcsDirectory) == '*Undefined*'">$(MSBuildThisFileDirectory)..\..\</RcsDirectory></PropertyGroup><UsingTask    TaskName="Rcs.RcsBuildTask"    AssemblyFile="$(RcsDirectory)Rcs.dll" /><Target AfterTargets="Build" Name="RcsBuildTask"><RcsBuildTask      ProjectPath="$(MSBuildProjectFullPath)"      RootNamespace="$(RootNamespace)"    /></Target></Project>

New doesn't added to project after installing this nuget.Any help will be appreciated