JERUSALEM — After a prolonged chill, security ties between Israel and China are warming up.

With Israel offering much-needed technical expertise and China representing a huge new market and influential voice in the international debate over Iran's nuclear program, the two nations have stepped up military cooperation as they patch up a rift caused by a pair of failed arms deals scuttled by the U.S.

The improved ties have been highlighted by this week's visit to Beijing by Israel's military chief and a training mission to Israel by the Chinese paramilitary force that, among other things, polices the restive Tibetan and Muslim Uighur regions. Prime Minister Benjamin Netanyahu is expected to travel to China in the coming weeks.

After their meeting Monday, both China's chief of staff, Gen. Chen Bingde, and his Israeli counterpart, Lt. Gen. Benny Gantz, hailed the growing ties and held out the possibility of even closer military cooperation.

Chen told the official China Daily that China "attaches importance to the ties with the Israeli military and is willing to make concerted efforts with the Israeli side to deepen pragmatic cooperation."

In a statement released by the Israeli military, Gantz mentioned a commitment to developing the relationship, including "joint courses that are scheduled to take place." It did not elaborate.

Such comments are a remarkable turnaround from just a few years ago, when ties deteriorated after the failed arms deals.

Israel and China established diplomatic relations in 1992, and the two countries traded military technology for nearly a decade. Some military analysts believe that Israel helped China develop its J-10 fighter plane during the 1990s, a claim that both countries have denied.

These ties suffered a blow in 2000 when the U.S. pressured Israel to cancel the sale of a sophisticated radar system to China, fearing it could alter the balance of power with Taiwan. The cancellation infuriated China, cost Israel hundreds of millions of dollars, and frayed ties.

Then, in 2005, the U.S. persuaded Israel not to service spare parts for unmanned aircraft drones already sold to China, concerned that it would upgrade China's airborne anti-radar capability. Israel officials say that Israel has since halted weapons sales to China.

But in recent months, relations have begun to improve. In June 2011, Israeli Defense Minister Ehud Barak traveled to China. Chen, the Chinese military chief, visited Israel in August, and in December, Israel's paramilitary Border Police unit hosted a delegation from the People's Armed Police.

During the monthlong course, "cadets were taught a variety of information, with an emphasis on fighting terror, dealing with disturbances, self defense, open field combat and more," according to an Israeli police statement. It was the first such exercise, police said.

This newfound cooperation has raised concerns among human rights advocates. Israel's Border Police serve on the front lines of anti-Israel demonstrations in the West Bank and have been accused of using excessive force dispersing crowds. It denies the allegations.

The People's Armed Police, or PAP, has also been accused of using excessive force, particularly in Tibet, a western region where the indigenous Buddhist population has pushed for independence.

Policing Tibet is a small part of a challenging mission. Believed to have as many as 1 million members, the PAP is responsible for asserting government control over a rapidly changing society beset by soaring numbers of protests, strikes and ethnic unrest by Tibetans and Muslim Uighurs on China's Central Asian frontier.

Set up in the early 1980s to take over domestic security from the armed forces, the PAP has been derided for much of its history as undisciplined. The units proved unfit to handle the Tiananmen Square democracy demonstrations in 1989, forcing the Communist Party to call in the People's Liberation Army.

In the past decade, the government has launched a full-force upgrade. It now has rapid-response, counterterrorism, anti-hijacking and other specialized units.

Nicholas Bequelin, a China researcher at Human Rights Watch, said PAP units engaged in "widespread abuses" in putting down a mass Tibetan uprising in 2008, using live ammunition against unarmed protesters, disappearances and other acts of disproportionate brutality.

He said the Israeli training "must include a human rights component, such as the principle of proportionate use of force."

Israeli officials rejected any notion of wrongdoing, saying that all cooperation was "transparent" and done with the full knowledge of the U.S. The officials spoke on condition of anonymity because they were discussing a sensitive diplomatic issue.

The Chinese Embassy in Tel Aviv did not respond to a request for comment.

According to Israeli diplomats and analysts, the interests on both sides are clear. Israel has a strong interest in getting closer to a rising world power, while China is interested in Israeli military and technological know-how.

"I'm sure Israel does whatever it can to let the Chinese know that despite limitations on military transfers, Israel still has a strong will to attain good relations," said Yoram Evron, a China expert at Haifa University and the Institute for National Security Studies, a Tel Aviv think tank.

He said he believes the warming ties were initiated by the Chinese, who were caught off guard by the Arab Spring protests convulsing the region in the past year and a half.

"Due to the Arab Spring, China may have the impression, a stronger impression than before, that Israel is relatively stable compared with other players in the region," he said.

An Israeli diplomat involved in Asian affairs said the security ties are part of a larger blossoming of relations. China is now Israel's third-largest trade partner, after the European Union and United States. Bilateral trade exceeded $8 billion last year, roughly 20 percent higher than the previous year.

While those figures are minuscule for China, the diplomat noted that China is very interested in some key industries in which Israel has expertise. He cited Israeli water technologies in agriculture, desalination and wastewater management.

He said Israel has signed number of trade agreements with China in recent years, including a new scholarship program to bring 250 Chinese university students to Israel annually. It also has expanded its diplomatic presence in China with a new consulate in the city of Guangzhou, and another one set to open in Chengdu next year.

Israeli officials acknowledged their motives go beyond trade. They said they routinely raise concerns about Iran's nuclear program with China, which is both a permanent member of the U.N. Security Council and which relies on Iran for roughly 10 percent of its oil supply.

Israel, like the West, believes Iran is trying to build a nuclear bomb, and has hinted it will attack Iran if it concludes that international diplomatic efforts to stop Iran have failed. An Israeli attack could disrupt the flow of oil and send global energy prices skyrocketing, a nightmare scenario for China.

So far, the Israeli lobbying has yielded mixed results. China has helped pass four sets of economic sanctions against Iran, but has tried to dilute the language.

"We would like to see them taking more concrete steps because they have clout over Iran," the diplomat said. "We explain that if the issue is not resolved, it might affect stability in the Middle East."