Brussels (AFP) -

"It is no secret that we have not yet found the way to work together on missile defence," NATO head Anders Fogh Rasmussen said after a meeting of the NATO-Russia council.

"However, ministerial discussions are valuable in addressing existing concerns and we need to continue to engage frankly and directly to overcome our differences."

Moscow fears that US-led plans for a missile defence system against attacks from outside Europe -- taken to mean from Iran or terrorist groups -- compromise its security.

Russian Defence Minister Sergei Shoigu made the point again on Wednesday.

"We failed to work cooperatively on this issue and Russian concerns are not being (taken into account)," Shoigu told a news conference after the meeting.

"Before studying missile defence projects, we want to have assurances that this US missile defence system is not against Russia," he added.

US Defence Secretary Chuck Hagel said separately that the missile defence project "remains on track", with work on a first installation in Romania due to begin next week.

At the same time, however, Hagel praised the work of the NATO-Russia Council, with the two sides having "many areas of common interest".

He said he had had a good meeting with Shoigu and the two men had agreed to hold regular video conferences and staff exchanges.

The aim was to "have a very open, and frank discussion... to anticipate problems rather than waiting for a crisis," Hagel said.

"We have differences and will continue to have," he added.

US missile plans in Europe have long been a sore point for Russia which charges that the missile shield is designed to reduce the deterrent effect of Moscow's arsenal and thus alter the balance of power on the continent.