Russian president`s vow to respond strongly to Washington`s missile shield plan in Central Europe has displeased US officials, reports say, according to Press-TV.

Dmitry Medvedev, in a gritty speech to Russia`s top diplomats on Tuesday, said that Moscow will vigorously defend its interests abroad and made clear that he would not soften the assertive policies that irked the West under his predecessor, Vladimir Putin.

He blamed the United States directly for chipping at the foundations of the security arrangements established in Europe at the end of the Cold War and said that it could collapse if the United States deploys the missile shield in Eastern Europe.

Medvedev added that Washington`s reasoning "does not satisfy us". He asserted that the US plan to place a tracking radar in the Czech Republic and missile interceptors in Poland are not actually meant to neutralize Iranian threat but aimed to weaken Russia`s nuclear deterrent.

"We will need to react to this adequately," he added.

"Russia has become stronger and is capable of assuming greater responsibility for solving problems on both a regional and global scale," Medvedev told over 200 Russian ambassadors and senior foreign ministry officials.

Moscow, sensitive to any Western military advance towards its borders, also opposes US-led moves to integrate ex-Soviet states of Georgia and Ukraine into NATO.

US Lieutenant General Henry Obering said the statements made by the Russian president are "increasingly aggressive".

Obering, who heads Pentagon`s Missile Defense Agency, said, "There is actually no justification, in our eyes, for some of his statements and some of his concern about these sites".

Trying to allay Russia`s concern, he said that the missile plan was aimed at countering a growing Iranian missile threat and not at Russia.

Obering said that the US is not exaggerating the Iranian threat. However, he argued a space-launch program announced by Iran could be used to develop the multi-stage technology needed for a long-range missile.