NATO has invited Russia to take part in its May summit on Afghanistan in Chicago, but Moscow says it is still undecided whether to accept the invitation.

NATO Secretary General Anders Fogh Rasmussen said during Thursday's meeting of the NATO-Russia Council (NRC) at the foreign ministers' level in Brussels that the alliance would like Russia to join the talks due on May 20-21, 2012.

The situation in Afghanistan will top the agenda of the summit, along with missile defense in Europe.

However, Russian Foreign Minister Sergei Lavrov declined to say if Russia would attend, RIA Novosti reported.

"I cannot understand why we are not invited to the regular meetings the experts and ambassadors hold here in Brussels, if we still present interest as a partner in the work on Afghanistan," Lavrov told a news conference in the Belgian capital.

"So, taking these aspects into account , we will consider this invitation and give our answer soon," he said.

RIA Novosti reminds that relations between NATO and Moscow have grown sour lately over the alliance's European missile shield plans, but the sides have cooperated closely in the war in Afghanistan.

Russia has provided its territory for NATO's Afghanistan-bound non-lethal supplies since 2009. Last year, Moscow also agreed to allow such cargo to cross Russia's territory in the opposite direction as the alliance is preparing to pull out its troops from Afghanistan.

Moscow is also preparing to allow NATO to use an airport in Ulyanovsk, the birthplace of Russian revolutionary Vladimir Lenin, to transit non-lethal cargo to and from Afghanistan.

Russian Prime Minister Vladmir Putin recently said Russia was ready to step up its efforts to help Afghanistan develop its economy and strengthen its military to fight terrorism and drug production.

During their Thursday meeting, the NATO and Russian foreign ministers "agreed that the stability of Afghanistan remains vital for all of us," Rasmussen said in a statement.

He told ministers Afghan helicopter maintenance engineers of the Afghan armed forces were currently starting training in the Russian city of Novosibirsk. The training program is being financed by the NRC.

Russia is delivering new Mi-17 helicopters to Afghanistan, paid for by the United States. Moscow signed a USD 367.5 M deal in 2011 with the U.S. Department of Defense to supply 21 Mi-17V5 transport/attack helicopters to be used in Afghanistan.

The NRC has also trained a total of 2,000 counter-narcotics personnel from Afghanistan and its neighboring states, Rasmussen said in his statement.

"Ministers looked forward to further cooperation on Afghanistan, including by taking into account the activities of relevant regional actors," he added.