LONDON, May 15 -- The United States and its European allies will impose "sectoral economic sanctions" if Russia or its "proxies" disrupt the elections in Ukraine, U.S. Secretary of State John Kerry said here Thursday.

"We are also working with Ukraine and the OSCE (Organization for Security and Co-operation in Europe) to protect the rights of all Ukrainian citizens and to make their voices heard through the ballot boxes in a legitimate election," Kerry told a press conference after a meeting with some of his European counterparts on Thursday.

"This morning we also underscore the vital importance of the free and fair presidential elections across Ukraine, on May 25, including, importantly, the eastern provinces," he added.

Calling on the Russians to "respect this process," Kerry continued, "We support the government in Kiev's efforts to reach out with serious, concrete plans for increased autonomy."

Also at a press conference on Thursday, British Foreign Secretary William Hague said the ministers agree "Russia's behavior towards the Ukrainian elections will determine whether or not wider economic and trade sanctions will be applied."

"We all agree to continue the preparations for the sanctions, while we urge Russia to stop any actions to prevent the elections going ahead peacefully," the foreign secretary noted.

Hague hosted the Friends of Syria "London 11" meeting Thursday, attended by 11 foreign ministers from the United States, Britain, France, Germany, Italy, Egypt, Jordan, Qatar, Saudi Arabia, Turkey and the United Arab Emirates.

The dispute between Ukraine and Russia has escalated since March following massive pro-Russian rallies in eastern and southern Ukraine, which demanded autonomy from the government in Kiev and closer ties with Russia.

In April, Ukraine, Russia, the United States and the European Union reached an agreement in Geneva calling for all sides of the conflict to refrain from violence.

On Tuesday, the Russian foreign ministry said in a statement it is extremely important to implement as soon as possible a roadmap proposed by the OSCE to solve the Ukraine crisis.

The ministry said Kiev had to immediately stop "reprisal raids" in the East, pull back troops from besieged cities and towns, free all political prisoners and stop "intimidating civilians."

The statement said Russia expects leaders of the self-defense forces in Eastern Ukraine to "react appropriately if Kiev takes these steps."