The United States has slightly reduced its numbers of strategic intercontinental missiles, bombers and nuclear warheads, but it continues to maintain a major advantage over Russia, according to figures released this week by the State Department.

In the eight months since the New Strategic Arms Reduction Treaty with Russia went into effect, the two countries have conducted dozens of on-site inspections of each other’s missiles, bombers, stored weapons and test sites. They have notified each other almost 1,500 times about missile movements, flight tests and other actions regulated by the treaty.

The implementation of the accord “has been going very well indeed,” said Rose Gottemoeller, assistant secretary of state for arms control, verification and compliance. But analysts cautioned that upcoming elections in the United States and Russia will make progress on arms control unlikely over the next two years.

Since February, according to State Department data released Tuesday, the United States has removed 60 nuclear-weapons delivery systems, mostly bombers, from the deployed category, leaving in place 822 land- and submarine-based intercontinental ballistic missiles and bombers.

The Russians have reduced their deployed systems by five, leaving 516. But Russia has increased by 29 its warheads deployed on strategic weapons; the United States has reduced that number by 10.

Overall, the United States has 1,790 deployed nuclear warheads, and Russia has 1,556. Under the terms of the treaty, both sides have to bring that number down to 1,550 by February 2018. Each also is required to reduce its deployed strategic delivery systems to 700, a provision Russia already meets.

“The U.S. edge is secure for the foreseeable future,” said Hans Kristensen, a nuclear arms specialist at the Federation of American Scientists.

Under the treaty, Russia and the United States are required to show each other their newest strategic nuclear delivery systems. In March, a Russian team inspected the B-1B heavy bomber at Davis-Monthan Air Force Base in Arizona. The exhibition was designed to show that the plane had been reconfigured so that it could not carry nuclear bombs and therefore should no longer be counted under the START treaty.

That same month, a U.S. delegation was shown the newest RS-24 road-mobile Russian intercontinental missile launcher at the Teykovo military base, 135 miles northeast of Moscow. They also went to the Votkinsk Machine-Building Plant, in central Russia, to view the missile.

The five major nuclear powers — Britain, France, China, the United States and Russia — have set up preliminary working groups as a first step toward substantive talks under the Nuclear Non-Proliferation Treaty, which calls for them to reduce and eventually eliminate nuclear weapons. Gottemoeller said the effort represented “baby steps.”