WASHINGTON: The United States said on Wednesday it has fresh sanctions ready to impose on Russia if Moscow does not take steps to de-escalate tensions with Ukraine, including halting the flow of fighters and arms to Ukrainian separatists.

A senior US official said on Friday that Washington had ramped up talks with the European Union about “scalpel” sanctions on Russia’s financial, defence and high-tech industries as more Russian military material has flowed into Ukraine.

Separatist rebellions erupted in eastern Ukraine in early April after street protests in Kiev toppled Moscow-backed leader Viktor Yanukovich, and Russia in turn annexed the Crimean peninsula. Eastern rebels have called for union with Russia.

“We need to see Russia secure its border, stop the flow of fighters and weapons into Ukraine and call on separatists to lay down their arms and release the OSCE hostages,” US State Department spokeswoman Marie Harf said on Wednesday.

Harf was referring to monitors of the Organization for Security and Cooperation in Europe, a rights watchdog that lost contact with two monitoring teams in late May amid intense fighting between the Ukrainian army and pro-Russian separatists.

Last week, the OSCE said it had re-established contact with the two four-person teams and demanded their immediate release.

“Those are the important actions we are looking for,” Harf added. “We have additional sanctions ready to go.” The spokeswoman did not provide detailed information about the sanctions. However, last week the senior US official said they were designed “to deny Russia the kinds of investment and next-generation technology that it needs to continue to grow.”

The US moves respond to what American officials last week said was Russia’s recent increase in support to Ukrainian separatists, including the provision of Russian tanks and the preparation of more tanks to cross into eastern Ukraine.

Harf on Wednesday said the United States had continued the arms flow from Russia to Ukraine and also said Russia had deployed some of its own combat troops near the border.

Published in Dawn, June 26th, 2014