Ukraine's leaders are puzzling over how to cut off Russian support for a separatist rebellion in the east of the country but one of its richest men thinks he has the answer.
Billionaire businessman Ihor Kolomoisky has suggested building a wall along the almost 2,000 km (1,200-mile) land border with Russia to prevent fighters and weapons flooding in.
The idea may sound absurd but Kolomoisky has offered to stump up 100 million euros ($136 million) to fund the two-meter (six-feet) high, 25-30 cm (10-12 inch) thick wall of reinforced steel, complete with electronic alarms, trenches and minefields.
What's more, it has been done before: Israel has constructed a barrier to keep out Palestinian militants; China built the Great Wall to stop invaders; and Soviet-led East Germany erected the Berlin Wall, though more to keep people in than out.
"We can take on this project from start to finish," said Alexei Burik, deputy head of the Dnipropetrovsk region where Kolomoisky is the governor, offering to lead construction work.
Ukrainian President Petro Poroshenko may or may not be about to build such a wall but the growing discussion of the oligarch's idea highlights deep security concerns in Ukraine, three months after Russia annexed the Black Sea peninsula of Crimea.
The Russian invasion of east Ukraine expected by many Ukrainians has not come. But in several weeks of fighting, pro-Russian separatists have seized a number of border posts, enabling them to bring in weapons and other supplies.
Securing the long and winding, and notoriously porous, border has become Poroshenko's most pressing problem as he tries to put down the rebellion and hold Ukraine together.
Kolomoisky, a 51-year-old banking, media, energy and metallurgy magnate with a fortune estimated by Forbes magazine at $1.8 billion, has presented his plan to Poroshenko and reckons the wall can be built in about six months.
Some analysts dismiss the idea as a stunt.
"In the short term, it cannot be done," said Volodymyr Fesenko of the Penta think tank. Another analyst, Mykhailo Pohrebinsky, said: "This is a public relations campaign meant to consolidate Kolomoisky's image as a Ukrainian patriot."
Despite such criticism, the proposal is not being dismissed in parliament as a crackpot idea.
"Whether or not it is Kolomoisky's project, a wall will be built to defend Ukraine from Russia's aggression," said Ivan Stojko, a parliamentary deputy from the Batkyvshina party led by former prime minister Yulia Tymoshenko.
Pavlo Rizanenko, a deputy from the Udar (Punch) party of former boxing champion Vitaly Klitschko, said: "I don't think Poroshenko has a monopoly on this idea. It's something that should have been done long ago."
Secure Border Before Truce
Poroshenko, who replaced a Moscow-leaning president toppled in February after street protests, has ordered the armed forces to secure the frontier and says a 250-km (160-mile) stretch of the border has already been taken back. Once the border is secure, a truce can start and peace talks begin, he said.
His comments signaled a continuation of his dual policy of talking peace while pressing a military campaign in the east.
He wants Ukraine to demarcate the border on its own side, and build unspecified infrastructure there, which could mean erecting fences in villages that straddle the border.
Russia has balked at Kiev's proposals for tightening border security and says its moves are meant to fuel tension. But for some Ukrainians, building a wall has a clear appeal.
"Either we build a wall and forget about Russia, or let these madmen in Donbass live under [Russian President Vladimir] Putin. I'd prefer the wall and would be ready to give them some money to help build it," said Irina Sorokun, a Kiev pensioner.