* U.S. to boost air defences against N Korea after threat
* To forgo some missile shield elements that upset Moscow
* Senior Russian MP says that won't appease Moscow
A change in the United States plans for an anti-missile shield in Europe will not prompt Russia to drop its opposition to the system, a senior lawmaker allied to President Vladimir Putin said on Sunday.
U.S. Defense Secretary Chuck Hagel said on Friday the Pentagon would add 14 new anti-missile interceptors in Alaska, among others, after North Korea had threatened a preemptive nuclear strike against the United States.
To free up funds for that, U.S. officials said they were forgoing development of a new interceptor that would have been deployed in central eastern Europe and has been a focus of Russia's concern that the shield would weaken its nuclear deterrent.
But Alexei Pushkov, head of the foreign committee in the Russian parliament's lower house, the State Duma, said the change would not dispel Moscow's concerns about the missile shield the United States and NATO are developing in Europe.
"It would be premature to say that something has fundamentally changed," said Pushkov, who is also member of the ruling United Russia party's parliamentary faction.
"The United States is readjusting the missile defence system due to financial and technology issues -- issues not related to the Russian position," he told Reuters.
A Russian diplomatic source said Moscow was looking into Hagel's announcement and would comment in coming days.
Cold War-era foes Moscow and Washington have long been at loggerheads over the shield in Europe and President Barack Obama's decision in 2009 to scale down plans of the Bush administration only offered a short-lived respite.
Washington has said the missile defence system in Europe, that was due to be completed in four phases by early 2020s and include interceptors in Poland and Romania, is meant to counter a potential threat from Iran and poses no risk to Russia.
But Moscow has said the system would eventually enable the West to shoot down some Russian intercontinental ballistic missiles (ICBMs), threatening Russia's security.
Some Russian officials have said they suspect that is the true aim of the system.
Pushkov accused the United States of repeatedly altering its reasoning on the need for the missile shield in Europe and said any installations in Poland and Romania would be too far away from Iran to intercept any missiles launched from there.
"That proves Russia was right from the start in doubting the U.S. reasoning... We don't like the fact that we are being presented with arguments all the time that sooner or later prove absolutely false," he said.
Ties between Moscow and Washington, both veto-wielding members of the U.N. Security Council, have soured since the return of Putin, a former KGB spy, to the Kremlin last May over human rights and security issues, including the war in Syria.
The tension has undermined a 2009 initiative by Obama to "reset" ties.
"The main problem of Russia-U.S. ties now is very low trust. Such steps help trust a bit so it may have some positive impact in some areas of cooperation," said Fyodor Lukyanov, editor of Russia in Global Affairs magazine.
Lukyanov said the part of an anti-missile shield in Europe that the Pentagon would now skip was the one causing most irritation in Moscow. But he added that was not enough to trigger a radical change of position from Russia.
"Just moving interceptors from one site to another fundamentally changes nothing from the Russian point of view," he said.