BEIJING — Last month, as running skirmishes between protesters and police turned downtown Hong Kong into a battleground, a red banner strung against government offices read like a warning emerging from a haze of tear gas.

“If we burn you burn with us,” protesters wrote in large white letters.

That message might as well have been aimed at Chinese leader Xi Jinping.

With violent protests roiling Hong Kong’s streets for the 10th consecutive week, posing the most serious challenge to the Communist Party in decades, Xi appears to be caught with no good options as he heads into one of the most politically sensitive periods of his tenure.

For Xi, an attempt to forcefully suppress the unrest with the Chinese military would end Hong Kong’s status as an international financial hub and deal a serious blow to his ambition of bringing Taiwan, the self-ruled island that split from mainland China in 1949, under Communist Party control.

In his second appearance in a week, a top official from China’s Hong Kong policy office, Yang Guang, reiterated Tuesday that Beijing maintained its support for Hong Kong’s embattled leader, Carrie Lam. Yang voiced tough warnings about the consequences of violent protests, but he appeared to play down the prospect of China’s mobilizing the People’s Liberation Army to quell the dissent.

Yet calm in Hong Kong appears to be more elusive than ever as the clock runs down on Beijing’s political calendar. The Communist Party is preparing for the 70th anniversary of the founding of the People’s Republic of China, an event the party plans to celebrate this fall with a massive military parade — and one that cannot be marred by embarrassing hitches, such as scenes of defiant protests in a major city.

If “our Pearl of the Orient” — as Chinese state media called Hong Kong in a recent propaganda push — were to still be seized by protests and strikes on China’s National Day, Oct. 1, it would directly undermine Xi’s narrative that a strong Communist Party under his muscular leadership is leading the Chinese people toward greatness and unity.

“On the one hand, Xi can’t let this drag on too long — he is pursuing the so-called China Dream to make China great again,” said Warren Sun, an expert on Chinese politics at Monash University in Australia. “On the other hand, he needs to be very careful because the international world, including Trump and Taiwan, are watching to see if he mishandles things.”

Along with the trade war with Washington, the predicament of how to manage Hong Kong, Sun said, will probably head the agenda at the Communist Party leadership’s secret annual meetings at the Beidaihe resort this month.

With the clock ticking, Beijing appears to be stuck in a holding pattern, even though its officials and state media have steadily dialed up nationalist rhetoric and sounded alarms about the “black hand” of the CIA orchestrating the chaos in Hong Kong.

Hong Kong’s government and police, said Yang, the policy official, are “completely capable of protecting law and order” by themselves.

Still, Yang appeared to strike a restrained note days after the Chinese army garrison in Hong Kong released a provocative video showing soldiers training to put down civil unrest. On Tuesday, mainland police in the Chinese tech hub of Shenzhen, just across the border from Hong Kong, released a similar video showing forces training to suppress rioters wearing yellow hard hats — something seen on the streets of Hong Kong.

In recent days, too, Hong Kong police have showed a waning tolerance for the protests and have significantly increased their use of force.

At numerous spots around the city Monday, rallies held alongside a general strike descended into chaos. Police said Tuesday that they had used 800 canisters of tear gas, fired 140 rubber bullets and launched other projectiles to deal with demonstrators the previous day. They had fired 1,000 canisters in the past seven weeks, between June 9 and Aug. 4, before Monday’s protests.

Police also arrested 148 people Monday, the biggest single-day roundup since the protests began some two months ago.

China promised Hong Kong a high degree of autonomy when it regained sovereignty over the territory from Britain in 1997. But many in Hong Kong are voicing anger at Beijing’s steady encroachment and increasing assertiveness in Hong Kong affairs.

The political crisis in the city was sparked by now-suspended plans to allow extraditions to mainland China. But it has grown into a wider movement against Beijing’s authoritarianism, with demands for greater democracy and investigations into police violence toward protesters.

Meanwhile, memories of China’s Tiananmen Square crackdown in 1989 run deep in Hong Kong, the only place in China’s territory where the hundreds of deaths are publicly commemorated each June.

Kwei-bo Huang, vice dean of international affairs at the National ChengChi University in Taiwan, said Xi is highly hesitant to use force in Hong Kong because it would wreak havoc on his efforts to persuade the Taiwanese people to embrace China under a deal that would promise the island a level of autonomy.

But Beijing is also under pressure to restore order.

“Xi is in a dilemma,” Huang said. “Does he want violent protests in Hong Kong distracting people from the so-called great achievements of the People’s Republic on its 70th anniversary?”

Xi could offer some sort of political compromise or crack down forcefully in Hong Kong, but he would have to do it soon, Huang said.

“Whatever impact cannot lead to anything bad for Xi’s big Oct. 1 ceremony,” he said.

Shibani Mahtani in Hong Kong contributed to this report.