Rasa Miskinyte spent last Saturday in a freezing forest near Lithuania's capital learning to gather water from a pond with a condom, to filter it through sand, charcoal and cloth, and to make her own stove from a beer can. She thought some basic survival skills would be helpful if Russian troops ever entered Vilnius and her family escaped into the woods.

“Russia is a very dangerous kind of neighbour,” said Miskinyte, a 53-year-old film producer. “They are always aiming at us.”

Across Lithuania, Latvia and Estonia, fears are intensifying that Moscow, after displaying its military might in Georgia, Ukraine and now Syria, could have the Baltic states in its sights next. Russian President Vladimir Putin has warned he wouldn't hesitate to defend Russians wherever they live, words that feel like threats since significant numbers of ethnic Russians live in the Baltics.

Young Lithuanian civilians in military fatigues practice insurgency tactics that they fear could be needed given Russia's resurgence, in the village of Pomarazai, some 25 km (15 miles) from the capital Vilnius, Lithuania (AP)

Whether the danger is real or just bluster remains to be seen. But in Lithuania, a country that experienced a Russian occupation before, some people aren't waiting to find out.

Young Lithuanian civilians are learning counterinsurgency tactics on weekends. Others, like Miskinyte, have taken steps to protect themselves. The government, in response to pleas from a fearful public, has issued a preparation manual.

Rimvydas Matuzonis directs a project that teaches weekend guerrilla warfare courses. He explained the resolve to be ready by citing a popular saying in the forests of Dzukija, the southern region where his father grew up.

“Spring will come, the cuckoo will sing and we will pave our roads with the corpses of Russian soldiers,” Matuzonis said.

Some in the Baltic states feel reassured by their Nato membership and aren't overly anxious about a pending Russian invasion. Others describe a dull anxiety that flares up only sometimes. But there are some who are truly afraid and already preparing for the worst.

When Russia annexed the Crimean Peninsula from Ukraine in 2014, Miskinyte packed a bag with bread, salt and some essential items and planned to flee to a village where she has a house. She urged relatives to join her there, if the Russians came for Lithuania next.

“In the village you always survive,” Miskinyte said. “There is land, there are vegetables. There is everything there.”

Lithuanian civilians learn how to filter dirty water during a survival course teaching them skills that some fear could be needed given Russia's resurgence, just outside of the capital Vilnius, Lithuania (AP)

The sense of vulnerability in much of Eastern Europe has been heightened by a feeling that the international order, which brought peace and economic growth after the collapse of the Soviet Union, is disintegrating. US President-elect Donald Trump, who has said he might not automatically defend the Baltic states, underlines the shift.

Exacerbating the dread lately is Moscow's move to build up troops and nuclear-capable missiles in Kaliningrad, a Russian region wedged between Nato members Lithuania and Poland.

Poland is creating a Territorial Defence Force to train thousands of volunteers for the kind of low-intensity hybrid warfare seen in eastern Ukraine, including cyber warfare. Also, some of the new volunteers will be assigned to protect Polish territory near Kaliningrad.

Young Lithuanian civilians in military fatigues practice insurgency tactics that they fear could be needed given Russia's resurgence, in the village of Pomarazai, some 25 km (15 miles) from the capital Vilnius, Lithuania (AP)

But the foreboding is no doubt greater in the ex-Soviet republics, whose decision to regain independence when the Soviet empire collapsed humiliated the Kremlin.

In response to calls for guidance from citizens fearing war, Lithuania's Defence Ministry issued a civilian manual that includes information on survival skills and recognizing Russian weaponry.

The best way to prevent war is to “demonstrate to the aggressor that we are ready to fight for our freedom, for every centimetre of our land,” Defence Minister Juozas Olekas said.

“The capabilities, the readiness, this is the only way to stop Russian aggression in the region,” Olekas said in an interview with The Associated Press.

Lithuania re-established a conscript army last year, but so many citizens have volunteered for military duty that a draft hasn't been necessary. Many civilians in the hugely patriotic nation of 3m people also remain eager to do their part.

Last weekend, in an area of pine woods and fields outside Vilnius, a group of young men donned military fatigues, loaded pellets into replica assault rifles and practiced counterinsurgency tactics.

Using armoured vehicles and other retired military equipment, they engaged in a mock battle, storming a position held by the enemy amid explosions and thick smoke. Target practice with real weapons followed.

Many of the young civilians say military exercises have been a hobby for years, a way to get outdoors and release stress after a week in the office. But they also said they want to be ready to defend their homeland.

Young Lithuanian civilians in military fatigues practice insurgency tactics that they fear could be needed given Russia's resurgence, in the village of Pomarazai, some 25 km (15 miles) from the capital Vilnius, Lithuania (AP)

Their instructors from Defence Project, a warfare training group, make clear the drills have a new urgency given Russia's assertiveness.

“We have a border not only with Russia, but also with Belarus, and we should be aware that the little green men might appear from other borders or even from within,” said Zilvinas Pastarnokas, a 45-year-old retired soldier who helped found the defence project.

Matuzonis, the group's director, said the will to resist comes naturally for a people that suffered Russian occupation in the past. Partisan warfare against Soviet rule continued for several years after World War II.

Many of the lessons Lithuania's soldiers and civilians are learning now were handed down by post-war partisans, knowledge preserved by the military. Ukrainians fighting pro-Russian rebels have shared new tactics.

Fears of stewing Russian aggression have raised questions about the loyalties of the ethnic Russians who live in Lithuania and make up about six per cent of the population. Many settled there when Lithuania was part of the Soviet Union and remained.

Lithuanian officials insist they are full citizens like everyone else and aren't under any suspicion, and ethnic Russians say they have very good interactions with Lithuanians.

Yet many Lithuanians fear if war ever came, ethnic Russians would side with Moscow.

Lithuanian Orthodox priest Josif Zeteisvili speaks during the Sunday mass at the Saint Panteleimon Orthodox Church in Visaginas some 150km (93 miles) northeast of the capital Vilnius, Lithuania (AP)

“The Russians will absolutely be on Putin's side. A few are pro-Lithuanian, but not many,” said Miskinyte, the film producer who took the survival course.

For their part, Lithuania's ethnic Russians decry what they call the “anti-Russian propaganda” of Lithuanian officials, and many hold pro-Kremlin views.

“Everything in the Lithuanian press is represented from the one side — that the Russians are the bad guys, that the Russians are coming, that Putin is always bad,” complained Roman Nutsubidze, 30, who moved to Lithuania as an infant.

Nutsubidze, who lives in the predominantly ethnic Russian town of Visaginas, expressed frustration that the West doesn't see Putin as a good leader who has restored national pride to the Russian people. He said he loves Lithuania, but thinks Putin has no reason to want to seize the Baltic states.

“I don't see what he has done bad,” Nutsubidze said. “I don't actually see it.”