Updated

The pro-Russia insurgency in eastern Ukraine decided Thursday to go ahead with Sunday's referendum on autonomy despite a call from Russian President Vladimir Putin to delay it.

While Putin's call on Wednesday to postpone the vote was seen as part of an effort to step back from confrontation and negotiate a deal with the West, he fueled tensions again on Thursday by overseeing military exercises that Russian news agencies said simulated a massive retaliatory nuclear strike in response to an enemy attack.

Putin said the exercise involving Russia's nuclear forces had been planned back in November, but it came as relations between Russia and the West have plunged to their lowest point since the Cold War.

On the ground in Ukraine, many have feared that the referendum could be a flashpoint for further violence between Ukrainian troops and the pro-Russia militants who have seized government buildings in about a dozen cities in the east.

The decision to hold the vote as planned was unanimous, said Denis Pushilin, co-chairman of the so-called Donetsk People's Republic.

He said the suggestion to postpone the referendum "came from a person who indubitably cares for the population of the southeast" of Ukraine and thanked Putin for his efforts to find a way out of the situation. "But we are just a bullhorn for the people," Pushilin said. "We just voice what the people want and demonstrate through their actions."

The question on the ballot is: "Do you support the act of proclamation of independent sovereignty for the Donetsk People's Republic?"

Despite the phrasing, the organizers have said that only after the vote will they decide whether they want actual independence, greater autonomy within Ukraine or annexation by Russia.

Putin on Wednesday also declared that Russia has pulled its troops away from the Ukrainian border, although NATO and Washington said they have seen no signs of this.

"I have very good vision but while we've noted Russia's statement so far we haven't seen any -- any -- indication of troops pulling back," NATO Secretary-General Anders Fogh Rasmussen said in a post on Twitter.

Russian Deputy Defense Minister Anatoly Antonov accused NATO and the Pentagon of deliberately misrepresenting the situation on the border and urged them "to stop cynically misleading the international community," the Interfax news agency reported.

Putin also spoke more positively about the Ukrainian interim government's plan to hold a presidential election on May 25, calling it a "step in the right direction," but reiterated Russia's contention that the legitimacy of the vote depended on Ukraine ending its "punitive operations" in the east and beginning a dialogue to assure the Russian-speaking population that their rights would be guaranteed.

A poll released Thursday showed that a strong majority of Ukrainians want their country to remain a single, unified state and this was true even in the largely Russian-speaking east where the pro-Russia insurgency has been fighting for autonomy.

The poll conducted last month by the Washington-based Pew Research Center found that 77 percent of people nationwide want Ukraine to maintain its current borders, while nearly as many, or 70 percent, in the east feel the same. Only among Russian speakers does the percentage drop significantly, but it is still over half at 58 percent.

The central government in Kiev has the confidence of only about 41 percent of Ukrainians, with a sharp divide between the west of the country, where support is 60 percent, and the east, where it is a low 24 percent, according to the poll.

Russia, however, is viewed with great suspicion, with three times as many Ukrainians surveyed saying Russia is having a bad influence on their country as say its impact is positive.

In Crimea, which Russia annexed in March following a referendum, 93 percent of people surveyed expressed confidence in Putin and said Russia was playing a positive role on the peninsula. Their confidence in U.S. President Barack Obama, on the other hand, was recorded at a dismal 4 percent.

In a parallel survey Pew conducted in Russia last month, 61 percent agreed that there are parts of neighboring countries that belong to Russia. The 1991 breakup of the Soviet Union left many ethnic Russians in other countries, including a swath of eastern and southern Ukraine that Putin had described as historically Russian territory.

In another echo of Putin, 55 percent of Russian surveyed said they saw the Soviet collapse as a great tragedy.

The poll in Ukraine was conducted April 5-23 among 1,659 adults, and the one in Russia April 4-20 among 1,000 adults. Both have a margin of error of about 3.5 percentage points.