In a Thursday morning update, the department tweeted: “Approximately 20 Russian Navy vessels are currently in the Black Sea operational zone, including submarines.
“The Bosporus Strait remains closed to all non-Turkish warships, rendering Russia unable to replace its lost cruiser Moskva in the Black Sea.
“Despite the embarrassing losses of the landing ship Saratov and cruiser Moskva, Russia’s Black Sea Fleet retains the ability to strike Ukrainian and coastal targets”.
The Defence Secretary told Sky News: “We have said we will source and supply, if we can, anti-ship missiles.
“It’s incredibly important that the grain that affects us all, the food prices, does get to get out of Ukraine, that the Russians can’t control the Black Sea”.
He said Russian ships must not be allowed to be “used to bombard cities”.
Ben Wallace said the worse Russia behaves in its invasion of Ukraine, the more the West will help Ukrainians defend themselves.
He told Times Radio: “What we were always careful to do is make sure that we calibrated whatever weapons we sent in.
“It’s important to link Russian behaviour with the response.
“If they do horrendous things, they must recognise that there will be an increase in weapons to the Ukrainians to see them off.
“And so, you know, if Russia continues to bomb indiscriminately people from the air – look what it’s done in Mariupol, for example – destroyed the city, then of course the West will respond more to Ukrainian requests for self-defence, and sometimes that will include planes and tanks.”
Mr Wallace said Britain will not provide planes, but it would have supported Poland in sending MiG-29 fighter jets to Ukraine.
The Defence Secretary stressed that the supply of weapons to help Ukraine defend itself against the Russian invasion is not a Nato effort and said Britain stands ready to send more.
Ukraine president Volodymyr Zelensky accused Russia of using gas and trade as a weapon against Europe after after Russia's state-run energy firm Gazprom cut gas supplies to Poland and Bulgaria, and threatened to do the same to other European nations.
European Commission President Ursula von der Leyen said it showed Russia was "unreliable" as an energy partner, and the White House said Russia was almost weaponising energy supplies.
Zelensky also claimed claimed Russian special services were behind a series of explosions in Transnistria.
Fighting continued in the country’s east along a largely static front line some 300 miles (480 kilometres) long.
Russia claimed its missiles hit a batch of weapons that the US and European nations had delivered to Ukraine.
Just across the border in Russia, several explosions at an ammunition depot in the Belgorod region were heard on Wednesday.
Explosions were also reported in Russia’s Kursk region near the Ukrainian border, and in Russia’s Voronezh region, authorities said an air defence system shot down a drone.