In fact, the bill passed recently by the lower house of Congress not only limits but bans the use of budget funds on joint projects with Russian Ministry of Energy. The reasons for this decision are not listed in the document. But all restrictions on cooperation with Russia set by the US lawmakers were related to the situation around Ukraine. At the same time, the bill contains a provision allowing to continue contacts with Russia, if the Minister of Energy finds that "such activities in the interest of US national security."
However, even with this amendment the Obama administration regarded the document as unacceptable.