NATO foreign ministers pressed Afghanistan Tuesday to sign an accord on the alliance's new role in Afghanistan and called for dialogue in Ukraine after Kiev ditched an accord with the EU, sparking violent protests.

NATO said recent developments in the former Soviet state had been discussed and a declaration agreed, even though Ukraine was not formally on the agenda.

"We condemn the use of excessive force against peaceful demonstrators in Ukraine," the declaration said.

"We urge the government and the opposition to engage in dialogue and launch a reform process," it said.

Ukraine is a partner of NATO, the military alliance formed in the Cold War to counter the Soviet Union, but Moscow jealously guards its influence in former Soviet states and trumped an EU association pact last week with a mixture of threats and inducements.

"We urge the Ukraine government to listen to the voice of its people," said US Secretary of State John Kerry.

There was "extraordinary support" for Ukraine, Kerry said, adding he hoped the country would soon get back on the road of integration with Europe.

The two-day meeting in Brussels is focused on Afghanistan and NATO's planned training and advisory mission after it ends its biggest ever combat operation there next year.

If that can be resolved, it will clear the decks for NATO leaders to set a new course for the alliance at a summit in late 2014.

Afghanistan troop status accord held up

The problem, however, is that Afghan President Hamid Karzai is refusing to sign a Bilateral Security Agreement required by Washington to set the legal and operational framework for the training force of up to 12,000 troops, likely to be mostly American.

Washington and NATO have made clear that without an accord, there is "no post-2014 mission," in which case both military and even development aid could be at risk.

NATO head Anders Fogh Rasmussen reiterated that position, stressing the need for Karzai to sign the agreement and soon.

"It is clear that if there is no signature ... there can be no deployment and the planned assistance will be put at risk," Rasmussen said.

"This is not fooling around, this is serious business," Kerry said, urging Karzai to sign the BSA in accord with the wishes of the "vast majority" of the country.

Both Kerry and Rasmussen stressed the practical issues involved -- the US and its NATO allies need time to put resources in place for the post-2014 mission and cannot be left hanging.

Neither would set a specific deadline despite being pressed on the issue, saying only that the sooner the better.

In 2011, the US government took the 'zero option' of complete withdrawal from Iraq when it could not get a troop status deal.

NATO officials put annual aid for the Afghan armed forces at $4.1 billion -- of which Kabul at best could only raise $500 million -- and $4.0 billion for development.

On NATO's future, a key issue is how to build on its active military role since the early 1990s, from the Balkans to Afghanistan and Libya, and safeguard gains in inter-operability and capability at a time when defence budgets are under strain.

The aim is a NATO which remains relevant and effective.

"We have got to ensure that we sustain NATO's military edge," a senior US official said.

"In the context of extreme budgetary constraints ... it is incumbent on us all to do more with (the money) that we have."

The 28 allies, plus NATO's partners and sometimes adversaries such as Russia meet for a second day Wednesday when Ukraine and Afghanistan may again figure prominently.

Missile defence, a hugely sensitive issue for Moscow, is also on the agenda given US and European concerns of a threat from Iran despite the recent signing of an initial deal on its contested nuclear programme.

Relations with Georgia provide another difficult issue as NATO seeks to maintain and boost ties with former Soviet states.

Following the NATO meeting, Kerry will travel to Moldova, which agreed a deal with Brussels last week despite intense Russian pressure not to.

"We are making this brief stop to demonstrate US support for the important choice that Moldova made," the US official said.