Public views of China and Russia have slipped considerably in the past year, according to a new BBC World Service poll across 21 countries.

Views of the U.S. have improved modestly over the past year but remain predominantly negative, even though the poll was taken after President Obama's election.

In last year's poll across the same countries, people leaned toward saying China and Russia were having positive influences in the world. But views of China are now divided, with positive ratings having slipped six points to 39 percent, while 40 percent are now negative. Negative views of Russia have jumped eight points so that now, substantially more have a negative (42%) than a positive view (30%) of Russia's influence.

Views of the U.S. showed improvements in Canada, Egypt, Ghana, India, Italy and Japan. On average across countries, positive views of the U.S. have risen from 35 percent to 40 percent, but they are still outweighed by negative views (43%, down from 47%).

As was the case last year, Iran, Israel and Pakistan are the three countries rated most negatively.

It should be noted that most polling occurred before Israel undertook its military operation in Gaza, and before the recent interruption in Russian gas supplies to Europe.

Germany is the country with the most positive image, with positive ratings rising from 55 percent to 61 percent on average. Every country polled has a favorable view of Germany.