US Secretary of State Condoleezza Rice has voiced concern about Russian legislation that could restrict the work of non-governmental organisations.
Ukraine has just joined a US-backed defence organisation
The bill has passed a first reading in the Russian parliament. It would tighten controls on branches of foreign NGOs and require them to re-register.
Ms Rice said she hoped Russia would understand the role of NGOs in ensuring a "stable democratic environment".
She was speaking in Ukraine - the third leg of a European tour.
She said the US government had expressed its concerns about the bill to Russia "at all levels".
So far her tour has been dogged by concerns about US treatment of terror suspects - especially the controversial policy of secret "rendition", whereby captives are transferred to third countries accused of using torture.
Ms Rice insisted on Wednesday that the UN convention banning torture and cruel treatment extended to American personnel interrogating detainees, regardless of where they were in the world.
Support for Yushchenko
Ms Rice praised the reforms pursued by Ukrainian President Viktor Yushchenko, the pro-Western leader who spearheaded the liberal "Orange Revolution" last year.
"We are certainly committed to Ukraine's full integration to the international economy and ultimately to Euro-Atlantic structures," Ms Rice said after talks with him.
She described Ukraine as a "strategic partner" for the US.
Ms Rice arrived from Romania, where she signed a deal granting the US access to local military bases.
Ms Rice arrived in Ukraine on the day the country joined a US-sponsored security body, the South-Eastern European Defence cooperation group (SEDM).
Ukrainian Defence Minister Anatoly Hrytsenko told his colleagues from the 10 other SEDM member-states that Kiev would increase its participation in regional security institutions.
US Defence Secretary Donald Rumsfeld, who was hosting the annual SEDM meeting in Washington, said Ukraine was capable of contributing significantly to the group's initiatives.
The organisation, which was formed a decade ago, includes Albania, Bulgaria, Croatia, Greece, Italy, Macedonia, Romania, Slovenia, Turkey and the US.