Times are hard at Ukraine's major trading port at Mariupol. In fact, it's almost dead - and workers say things have not been this bad for decades.

"If it carries on like this, the number of shipping companies working with us will plummet next year," says engineer Maryna Pereshyvatlova, who has worked here for 32 years.

Ever since conflict broke out in the east when pro-Russian separatists seized parts of the Donbas region, the port has been starved of coal shipments.

Then the Russians built a bridge over the Kerch Strait to Crimea, limiting the types of merchant ships that could enter the Sea of Azov.

But the final and most painful blow to the local economy came last month.

Three Ukrainian ships were fired on and seized near the strait in international waters off Crimea.

Three of the crew were wounded, and all 24 are being held in Moscow at the centre of an international row.

For more than a week afterwards, Russia stopped commercial vessels at the entry point to the Kerch Strait from sailing to Mariupol and another Ukrainian port to the west, Berdyansk.

Eventually, they let vessels pass the strait, but the reprieve came too late.

"There are almost no ships now," says port director Oleksandr Oleynyk.

And then there are the inspections.

Russian officials do not tell their Ukrainian counterparts when inspections will take place, which boats they will hold, or for how long.

Each day of delay costs the shipping companies between $15,000 and $20,000 (£12,000-£16,000).

"After such big losses, companies don't want to sail here any more. This uncertainty is especially hard for us," Mr Oleynyk says.

I watched as a single solitary vessel was loaded with sunflower products, in a port that used to host dozens of ships every day.

For the crew an unknown journey awaits as they set off from Mariupol for the Kerch Strait and beyond. They do not know how long they will be held at the entry point to the strait, or how much money they might lose.

The port administration says it has lost around 40% of its metal shipments in the past few weeks.

For Mariupol's port workers, too, the situation is desperate. The jobs of 4,000 workers at the port are directly threatened by Russia's actions.

They need a political solution to ease tensions between Russia and Ukraine.

Many here accuse Russia of deliberately strangling this port and worsening the situation in eastern Ukraine.

So far, the port has escaped layoffs, but nobody can predict how long it can survive with trade at such a slow pace.

"We just hope for international pressure on Russia. We need to set off alarm bells," says engineer Maryna Pereshyvatlova.

The port's new neighbours are the Ukrainian navy.

Two naval vessels that managed to get through the Kerch Strait in September are now anchored next to the trade terminals.

They sailed from Mariupol to meet their colleagues on 25 November, but the three boats never arrived.

"It was very sad for us when we realised they would not come," Captain Oleksandr Grygorevsky says.

Mariupol was already struggling before the flare-up in the sea.

Only 20km (12 miles) away lies the frontline in a conflict that has dragged on for four years between Ukrainian forces and pro-Russian separatists.

Now the situation at the port is so bleak that any future for this industrial stronghold in the Sea of Azov looks uncertain.

When Russia seized the three Ukrainian boats, Ukraine's president imposed martial law in this region and several others.

But locals here are far more worried for their future lifeline to the sea than by the restrictions from Kiev.