Military spending in Ukraine and several other Central and Eastern European countries rose sharply in 2018, largely in reaction to perceived threats from Russia, a leading research institute says in a new report.

The Stockholm International Peace Research Institute (SIPRI) said on April 29 that spending by Ukraine rose 21 percent to $4.8 billion last year, in line with similar percentage rises in Bulgaria, Romania, Latvia, and Lithuania.

"The increases in Central and Eastern Europe are largely due to growing perceptions of a threat from Russia," said Pieter Wezeman, a senior researcher at SIRPI. "This is despite the fact that Russian military spending has fallen for the past two years."

Spending in Bulgaria, Romania, Latvia, and Lithuania rose from 18 percent to 24 percent each, SIPRI's Trends in World Military Spending 2018 said. Poland’s expenditures rose 8.9 percent to $11.6 billion.

Russia's military spending, meanwhile, dipped 3.5 percent from 2017 to 2018, but its outlays remained the sixth-highest in the world at $61.4 billion.

Western-supported Ukraine has struggled since 2014 against Russia-backed separatist militants who seized parts of eastern Ukraine in a conflict that has killed more than 13,000 people. Russia also seized and annexed Ukraine’s Crimea region in 2014.

Countries with the highest relative increases in military spending in 2018 included Armenia (up 33 percent), Bosnia-Herzegovina (26 percent), Bulgaria (23 percent), Ukraine, Romania (18 percent), and Kazakhstan (16 percent).

Armenia's total expenditure, at $609 million, was 4.8 percent of gross domestic product (GDP), making its military spending burden among the top 10 in the world, along with Russia at 3.9 percent.

Iran’s military spending declined 9.5 percent in 2018 to $13.2 billion as the country’s economy and its currency suffered in the face of renewed financial sanctions imposed by the United States.

Washington accuses Tehran of attempting to develop nuclear weapons in defiance of UN resolutions and of fomenting extremist violence in the region. Iran denies the charges.

After years of declines, Afghanistan’s military increased 6.7 percent in 2018 to $198 million.

Western-backed Afghanistan continues to struggle against Taliban and other extremist groups attempting to overthrow the government in Kabul.

However, its overall military burden remained relatively low at 1 percent of GDP. Much of its military expenses have been assumed by the United States, which has had a military presence in the country since a 2001 invasion drove the Taliban from power.

Pakistan increased spending by 11 percent to $11.4 billion, making it the 20th-largest spender in the world. Spending rose to 4 percent of GDP -- the highest since 2004.

Meanwhile, neighbor and bitter nuclear rival India increased military outlays by 3.1 percent to $66.5 billion and 2.4 percent of GDP.

Violence flared between India and Pakistan early this year in and around the disputed region of Kashmir. The region is administered in parts by each country but claimed in its entirety by both.

Worldwide, the report said military spending rose 2.6 percent in 2018 to $1.822 trillion, or 2.1 percent of global GDP.

The five largest spenders were the United States, China, Saudi Arabia, India, and France -- which combined accounted for 60 percent of global military outlays.

Military expenditures by the United States (up 6.4 percent to $649 billion) rose for the first time since 2010. Spending was 3.2 percent of GDP.

China's spending rose 5 percent to $250 billion -- the 24th consecutive annual increase for the Asian power.