Ukrainian President Volodymyr Zelensky has temporarily lifted a visa requirement for foreign nationals who wish to join Ukraine's "International Defence Legion" to fight against Russia.
Zelensky also announced Monday he will release prisoners with combat experience to defend Ukraine.
"Under martial law, participants in hostilities—Ukrainians with real combat experience—will be released from custody and will be able to compensate for their guilt in the hottest spots of war. All sanctions are lifted from some people who took part in the anti-terrorist operation. The key now is defense," he said.
The Ukrainian government has also been providing some of its citizens with basic military training.
Meanwhile, authorities in Kyiv, Ukraine's capital, which has about 3 million people, have been handing out weapons to anyone willing to defend the city as Russian troops close in.
Zelensky, in a video address late Monday, said Russian forces have intensified their shelling of Ukraine while the talks were underway. He also said Russians have shelled the city of Kharkiv with rocket artillery.
Donetsk and Luhansk, located in the mining area of Donbass, declared independence from Ukraine in April 2014. The move was in response to a coup in February 2014, when anti-Moscow, pro-EU factions overthrew then-Ukrainian President Viktor Yanukovych's government.
After the breakaway, the Ukrainian military was deployed to fight the rebels in the Donbass, resulting in heavy shelling and skirmishes. More than 10,000 civilians have died since the fighting began. Ukraine accused Russia of being responsible for the escalation of the conflict but Moscow has denied any involvement.
In September 2014, Ukraine and the breakaway regions held extensive talks in Minsk, Belarus, and agreed to Minsk I, a 12-point ceasefire deal. But the deal fell apart with violations by both sides.
In February 2015, Russia, Ukraine, the Organisation for Security and Cooperation in Europe (OSCE), and leaders of the Donetsk and Luhansk breakaway regions signed Minsk II, a 13-point ceasefire deal. While heavy fighting subsided, it never completely ceased.