WASHINGTON, May 20 - The United States continues to see no evidence that President Vladimir Putin has pulled Russian forces near Ukraine back to their bases, a senior U.S. military official said on Tuesday, a day after the Kremlin announced Putin had ordered the pullback.

"As of this morning, (we see) no evidence that Putin is withdrawing forces," Reuters reported, citing the official on condition of anonymity.

Moscow has massed tens of thousands of troops near border regions where pro-Russian separatists have declared independent states. Coming in the wake of Russia's seizure of Ukraine's Crimea, that has fuelled fears in Kiev and western nations that the troops could be used to invade in support of rebels.

The crisis in Ukraine is sure to be central during discussions among senior military officials at NATO headquarters this week. General Martin Dempsey, the top U.S. military officer, is in Brussels for the NATO discussions.

The United States and European Union have warned Putin's government against interfering with Ukraine's presidential elections on Sunday.

The election in Ukraine will deepen political divisions in the country if there is no end to hostilities and a "road map" to end the crisis is not implemented, Reuters quoted a senior Russian official as saying on Tuesday.

Deputy Foreign Minister Grigory Karasin's remarks were the latest from Moscow to cast doubt on whether Russia will consider the election legitimate.

In a report on talks between Karasin and British ambassador to Russia Tim Barrow, the Foreign Ministry underlined the importance of the "road map" drawn up by the Organization for Security and Cooperation in Europe (OSCE) and constitutional reforms following an agreement reached at talks in Geneva.

"Without the implementation of these agreements, and the immediate cessation of hostilities by (Ukrainian) army units southeastern regions, the May 25 election can only worsen the differences in the country," the ministry said.

At the talks in Geneva, the United States, Russia, Ukraine and the European Union agreed moves to ease tensions in Ukraine, following Russia's annexation of the Crimean peninsula and the seizure of buildings in the east by pro-Russian forces.

President Vladimir Putin has said Sunday's election could be "a step in the right direction" but other Russian officials have signaled Moscow may not recognize the outcome, especially if Kiev continues to use the armed forces in eastern Ukraine.

The pro-Western authorities in Kiev, who are not recognized by Moscow, have deployed military and security forces in the east to try to regain control of buildings seized by the pro-Russian separatists.

The Russian Foreign Ministry said these operations "block any real steps towards de-escalation of the situation".

Russia also wants constitutional reforms to give more autonomy to mainly Russian-speaking regions in the east.

Putin declared the right to send forces to Ukraine to protect Russian-speakers if necessary in March and quickly annexed Ukraine's Crimea region, after a pro-Russian president was toppled in street demonstrations in Kiev in February.

Armed rebels, many led by a Muscovite enthusiast of historical battle re-enactments, have seized towns and cities in eastern Russia and held a vote on independence which Western countries describe as a sham.

NATO and the United States say previous Russian pledges to pull back troops - including an announcement by Putin himself on May 7 that they had already been withdrawn - produced no significant withdrawal. (rt/ez)