There are no signs that Russia has pulled its troops back from the Ukraine border, NATO said Monday.

NATO is urging Russia to honor its word and withdraw its troops from Ukraine's eastern border, according to CNN.

NATO Secretary General Anders Fogh Rasmussen said there is currently no evidence that Moscow has followed its pledge to remove troops from the border. However, Kiev said it's keeping close tabs on the situation to make sure the troops are returning to their bases.

Rasmussen said Moscow needs to withdraw troops, and that he would "be the first" to welcome the move.

"I think it's the third Putin statement on withdrawal of Russian troops ... but so far we haven't seen any withdrawal at all," Rasmussen said.

"Withdrawal of Russian troops will be the first step to de-escalating the situation," he added.

He said that Russian and Ukrainian separatists should "practice restraint" ahead of Ukraine's presidential election, which is planned for Sunday.

"We urge the armed pro-Russian separatist groups to stop their illegal activities. ... Russia should stop their support for these armed groups," he said.

"Russia should demonstrate a clear will to let the presidential election to go forward," he continued. He added that the election is the best chance to find a long-lasting solution to the escalating crisis.

Russian President Vladimir Putin amassed 40,000 troops along the border in east Ukraine prior to the election, which was defended by Moscow. Russia said the troop surge was a "routine exercise" that has now ended. Putin spokesman Dmitry Peskov said the troop withdrawal has begun, but will take time to complete.

Putin said he was going to pull out troops two weeks ago, but NATO and Western officials say that have not seen any evidence that troops are withdrawing.

A senior U.S. administration official also doubted Russia's claim that the troop increase was a routine exercise.

"They have not been conducting routine training activities," the official said. "They've been up on the border in a menacing posture, and we've been concerned about this military buildup and have been consistently calling on Russia to remove its troops back to their home bases and end this threatening behavior."

The official added that the White House will monitor the troops closely to see if they withdraw.

The United States and other Western nations have put sanctions on Russia due to the annexation of Crimea, and are threatening to impose additional sanctions if Russia fails to withdraw troops from the Ukraine border.

Russian officials have said they believe they have the right to protect Russian citizens and Russian-language speakers in east Ukraine.

There have been ongoing reports of violence and human rights abuses in Ukraine's eastern cities. Pro-Russia separatists have repeatedly had violent clashes with Ukrainian nationalists, with the latest incident occurring Saturday.

Pro-Russia separatists clashed with Ukrainian border guards Saturday when Valeriy Bolotov, the self-declared governor of the Luhansk's People's Republic, was detained. Pro-Russia separatists attacked the guards, and eventually freed Bolotov. He is wounded, and was reportedly taken to Russia to receive medical treatment.

Valentyn Nalyvaichenko, the head of the Ukrainian Security Service, also said anti-terrorism operations began in April in Donetsk and Luhansk, which have killed 24 Ukrainian servicemen.

The Russian Foreign Ministry also accused Ukrainian troops of attacking Ukrainian citizens.

The United Nations released a report Friday about the increasing human rights violations in Ukraine, saying there are more recorded cases of killings, torture, beatings, sexual harassment and threatening of the press.