U.S. Secretary of State Hillary Clinton said on Thursday she had expressed well-founded concerns about the conduct of Russia's parliamentary election earlier this week.

Speaking after Russian Minister Vladimir Putin accused the United States of spurring protests over the vote by voicing serious concern about its conduct, Clinton said the United States was not alone in expressing concerns.

Human rights is part of who we are. And we expressed concerns that we thought were well founded about the conduct of the elections, she said.

We are supportive of the rights and aspirations of the Russian people to be able to make progress and realise a better future for themselves.

Clinton also said that U.S.-Russian disagreement over the Western alliance's plans for a missile defence system in Europe did not justify Russia taking military counter-measures.

While repeating NATO's desire to cooperate with Russian on the project, she said she had made clear at a meeting of NATO foreign ministers with their Russian counterpart Sergei Lavrov that the United States would go ahead with deploying missile defences to defend NATO territory.

She said the system will not and cannot affect Russia's strategic balance.

It does not affect our strategic balance with Russia and certainly is not a cause for military countermeasures, she said, referring to Russian threats to deploy missiles near NATO territory.

Last month Russian President Dmitry Medvedev said he would arm Russia with missiles capable of countering the U.S. shield and set up an early-warning radar system in its Baltic enclave of Kaliningrad, which borders Lithuania and Poland.

(Reporting by Arshad Mohammed, David Brunnstrom and Sebastian Moffett)