President Barack Obama on Monday announced notable steps to upgrade U.N peacekeeping, with his administration saying more than 50 countries have pledged to contribute more than 40,000 new troops and police to serve in some of the world's most volatile areas.

But there was no sign the U.S., which pays a quarter of the peacekeeping budget, would put more of its own troops into the field.

The United States chaired a high-level meeting to strengthen and modernize peacekeeping, whose nearly 125,000 personnel increasingly face threats from extremist groups while being severely stretched in personnel and equipment. Deployments to crises can take several months.

And a series of sexual abuse allegations against peacekeepers has brought new concerns about a long-standing problem that Obama called "an affront to human decency."

Obama's presence at Monday's meeting, shortly before his first face-to-face meeting with Russian President Vladimir Putin on the sidelines of an annual U.N. gathering of world leaders, was the latest sign of high-level U.S. interest in the issue.

Putin did not attend the meeting - the only leader of the five permanent members of the U.N. Security Council, which approves peacekeeping missions, not to be there.

For months, officials such as the U.S. military's top officer and U.S. Ambassador Samantha Power have pressed countries, especially European ones, to contribute more. European countries contributed more than 40 percent of U.N. peacekeepers two decades ago but now provide less than 7 percent.

The U.N. has no standing army, meaning that it's up to the U.N.'s 193 member states to supply people and equipment.

Monday's pledges of new troops and police significantly exceed the 10,000 goal that U.S. officials had mentioned. In addition, the dozens of leaders from India, Britain and China and elsewhere said they would contribute the kinds of more sophisticated equipment the U.N.'s 16 peacekeeping missions say they need: Special forces, intelligence units, engineering skills, airlift capacity, field hospitals and even unarmed drones.

Overall, countries pledged more than 40 helicopters, 15 engineering companies and 10 field hospitals, the U.S. ambassador to the U.N., Samantha Power, announced at the end of the meeting.

Obama said the U.S., which contributes less than 100 troops and police, will contribute $2 million for training of African forces for peacekeeping and $2 million for training on countering improvised explosive devices, among other support.

The United States and European countries have pulled back from peacekeeping operations over the past decades after disastrous losses of soldiers as happened in Somalia.

Chinese President Xi Jinping made perhaps the largest commitment, saying his country would establish a permanent 8,000-strong rapid deployment force to respond to crises anywhere in the world and to provide $100 million to fund a similar force under the African Union.

In addition, Xi said China would furnish more helicopters and other equipment and provide funding, training and equipment for 10 mine-clearing operations.

Other announcements included Britain committing 250 to 300 troops to the U.N. mission in South Sudan, drones and a signal communications unit from Pakistan, an infantry battalion and a helicopter from Italy and engineering support or personnel from South Korea, Japan and Sri Lanka.