3 pro-Russian fighters die in Black Sea base attack

Three pro-Russian militants died and 13 were wounded when Ukrainian troops repelled an attack on a National Guard base in the Black Sea port of Mariupol, Ukraine's interior ministry said Thursday.

A crowd of around 300 men armed with stun grenades and Molotov cocktails attacked the base, in the south-east part of the country late Wednesday, the interior ministry said in a statement. Servicemen inside fired warning shots but the attackers did not stop the assault and the army had to respond, it said.

There were no casualties among the Ukrainian servicemen, the ministry said, and 63 attackers were detained.

Speaking at the parliament Thursday morning, acting President Oleksandr Turchynov said the pro-Russian gang attempted to storm the base three times and carried automatic weapons.

Footage from outside the base on Thursday night showed an unidentified man who acted as an intermediary coming out of the building to the crowd and speaking to masked men armed with assault rifles. He told them the military asked for 10 minutes to think over an unspecified ultimatum and the masked men said they did not want any bloodshed.

Several minutes afterwards, the crowd, mainly made of masked men young armed with bats and sticks, started throwing Molotov cocktails at the base's gate and trucks parked in front of it. Sounds of gunfire were heard in response.

The skirmishes come after the Ukrainian government announced an operation to retake control of Slovyansk and other cities in the restive east.

The latest unrest came as diplomats from Ukraine, the United States, the European Union and Russia prepared to meet Thursday for the first time over the burgeoning crisis that threatens to roil the new government in Kiev. With Ukraine struggling to contain the pro-Russian uprising, the Obama administration has said it is readying additional sanctions against Moscow in the coming days.

Just before sitting down for the four-way talks, the U.S. announced on Thursday morning it would also offer Kyiv non-lethal military aid but urged the country's leaders to continue to act in a "measured and responsible way."

A well-armed, Russia-backed insurgency has sowed chaos in eastern Ukraine in the past weeks. Militants have taken control of police stations and administrative buildings in at least 10 towns in the region, including Mariupol near the Russian border.

With tens of thousands of Russian troops deployed along the border with Ukraine, there are fears the Kremlin might use the instability in the predominantly Russian-speaking region as a pretext for seizing more territory beyond its annexation of Crimea last month.

In a marathon question and answer session on Russian state television Thursday, Putin accused Ukraine's leaders of committing a "grave crime" by using its army to try to quell unrest in the east. He also reiterated his right to send Russian troops into Eastern Ukraine should the situation call for intervention. But, he said, "I really hope that I do not have to exercise this right and that we are able to solve all today's pressing issues via political and diplomatic means."

On Wednesday, throngs of residents in the eastern city of Kramatorsk encircled a column of Ukrainian armored vehicles carrying several dozen troops. Soon after, masked gunmen in combat gear reached the site. Without offering resistance, the Ukrainian soldiers surrendered the vehicles to the militiamen. On the outskirts of Kramatorsk, troops at 14 Ukrainian armored vehicles were surrounded by a crowd of local residents. To end the standoff, Ukrainian servicemen handed over the magazines from their assault rifles to pro-Russian militia and left.

Turchynov told the parliament on Thursday the brigade that laid down its arms will be disbanded and its members will face trial.

The Associated Press