By Olesya Astakhova and Anne Kauranen
HELSINKI (Reuters) - Russian President Vladimir Putin said on Wednesday that the United States was now in a position to deploy a new land-based cruise missile in Romania and Poland, a scenario he considered a threat that Moscow would need to respond to.
The Pentagon said on Monday it had tested a conventionally-configured cruise missile that hit its target after more than 500 km (310 miles) of flight, its first such test since the demise of a landmark nuclear pact this month.
The test followed the U.S. formally withdrawing from the Cold War-era Intermediate-Range Nuclear Forces Treaty (INF) on Aug. 2 after accusing Moscow of violating it, a charge dismissed by the Kremlin.
Putin, speaking during a visit to Helsinki, said that Washington could potentially now use existing launch systems in Romania and Poland to fire the new missile, meaning it could deploy it easily and swiftly if it chose to.
"Launches of this missile can be carried out from (launch) systems already located in Romania and Poland. All you have to do is change the software. And I don't think our American partners will inform even the European Union about this. This entails new threats for us that we must react to," Putin said.
The test would have been banned under the INF, which prohibited land-based missiles with a range of between 310 and 3,400 miles, reducing the ability of both countries to launch a nuclear strike at short notice.
The United States has said it has no imminent plans to deploy new land-based missiles in Europe.
Putin was speaking to reporters following talks with his Finnish counterpart Sauli Niinistö.
The Russian leader used a joint news conference to defend the authorities' response to a series of political protests in Moscow and to reassure people that an accident at a military testing site in northern Russia this month did not pose any threat to neighboring countries or people living nearby.
(Writing by Tom Balmforth; Editing by Andrew Osborn)