MOSCOW (Reuters) - Emergency workers toiling to clean up an oil spill in the Black Sea have detected seven new slicks, a Russian official told the TASS state news agency on Friday, as authorities struggle to mitigate the effects of the nearly month-old disaster.

Fresh oil started pouring from a stricken Russian tanker in the Black Sea on Friday, said officials in Moscow, as Ukraine warned of "terrible environmental consequences" from the spill.By trying to "conceal the terrible environmental consequences" Moscow had left the entire Black Sea region vulnerable to the fallout,

Russia has formed a new government commission to coordinate clean up of the biggest spill of oil products in the Black Sea in recent history.

Russia declared a regional state of emergency on Saturday in Crimea, which it seized from Ukraine in 2014, as workers cleared tons of contaminated sand and earth on either side of the Kerch Strait following an oil spill in the Black Sea last month.

The sanctions imposed by the United States on January 10 against the Russian oil sector have halted about one-tenth of Russia's shadow fleet. The value of the oil it transports could exceed $3.5 billion.

Sanctions imposed by the United States on January 10 against the Russian oil sector have halted about one-tenth of Russia's shadow fleet, which transports oil worth up to $3.5 billion. The new sanctions may significantly disrupt Russian oil supplies,

Russian seaborne oil exports may decrease in the coming weeks after the United States imposed sanctions on two of Russia’s largest exporters and about 160 tankers in the shadow fleet, Bloomberg reports.

Sanctions imposed by the United States on 10th January against the Russian oil sector have halted about one-tenth of Russia's shadow fleet. The value of the oil it transports could exceed £2.9 billion.