Error in using react-bootstrap

I'm using React-bootstrap package on my Keystone.JS project. To test I tried putting a button in my index page. However, I get the following warning:

Warning: Unknown props bsStyle, active, block, navItem, navDropdown, bsClass on tag. Remove these props from the element.

This is the code where I use Button:

var React = require('react');
var Layout = require('../../layouts/defaultLayout');
var ReactDOMServer = require('react-dom/server');
var Button = require('react-bootstrap').Button;

module.exports = React.createClass({
    render: function () {
        return (
            <Button bsStyle="primary">Default button</Button>
        );
    }
});

What am I missing? Thanks for the help.