Poland's foreign minister has warned Russia could face even further sanctions unless Moscow's policy in Ukraine changes.
Grzegorz Schetyna was speaking to Polish broadcast Polsat News on October 7.
Breaches of a cease-fire in eastern Ukraine have renewed Western diplomatic pressure on Moscow.
Western states accuse Russia of giving military support to the rebels, an allegation the Kremlin has denied.
"If Russia does not change its policy, sanctions will be toughened and they will make themselves felt even more in Russia," Schetyna said.
"All the European countries are speaking with one voice, together with Australia, the United States and Canada. The free world says 'no' to this kind of policy," he said. "The Polish viewpoint is shared by other countries."
Meanwhile, more breaches of the cease-fire, which came into effect one month ago, have been reported.
Defense officials in Ukraine said on October 7 that pro-Russia separatist fighters are continuing efforts to capture the airport in the main rebel-held city of Donetsk.
Security spokesman Andriy Lysenko said rebels fired on the terminal from tanks, artillery systems and multiple rocket launchers.
A senior U.S. diplomat visiting Ukraine called for an end on the assault on the airport, which remains under the control of government forces, and for hostilities to be suspended in other nearby towns.
In a veiled reference to Russia, U.S. Assistant Secretary of State Victoria Nuland demanded that foreign armed forces be pulled out of Ukraine.
"The shooting has not stopped, and the shooting must stop," Nuland told students at a university in Kyiv. "All foreign forces and foreign equipment must be withdrawn."
The Organization of Security and Cooperation in Europe said it should be able to secure two drones that will enable it to improve efforts to monitor violations of the cease-fire agreement.
Ukrainian President Petro Poroshenko told a delegation of officials from OSCE member states on October 7 that he eventually wanted to see 1,500 observers deployed in the east and that at least 29 drones be put at their disposal.
Since unrest began, Ukraine has appealed for a broad array of foreign support, including military aid.
In a related development, a convoy of 112 trucks carrying German aid destined for eastern Ukraine crossed into the country from Poland on October 7, the Development Ministry in Berlin said.
With reporting by TASS and Reuters