Malaysia - Malaysia deployed extraordinary security measures around Kuala Lumpur on Friday as world leaders arrived for a pair of weekend summits amid fresh attacks by Islamist militants.

Malaysia’s police chief cited unconfirmed reports of an “imminent terrorist threat” in the country, following last week’s attacks in Paris and the downing of a Russian airliner over Egypt by Islamic State militants.

Some 4,500 soldiers were deployed or on standby to secure the summit, in addition to thousands of police who have fanned out around the Kuala Lumpur City Centre. The site is home to Petronas Towers, once the world’s tallest buildings, and a convention center where the summits are taking place.

The leaders of 18 countries, including U.S. President Barack Obama, Japanese Prime Minister Shinzo Abe and Chinese Premier Li Keqiang are attending the annual Association of Southeast Asian Nations (ASEAN) meeting followed by the East Asia Summit.

Shortly after Obama arrived, reports from the African nation of Mali said gunmen shouting Islamist slogans attacked a luxury hotel in the capital of Bamako, taking 170 guests and hotel staff hostage. It was not immediately clear who the gunmen were affiliated with.

Obama has been briefed by his national security advisor on the incident, a White House official traveling with the President said.

Both the APEC meeting and the ASEAN summit typically focus on economic issues but have been overshadowed by global efforts to combat Islamic State following the attacks in Paris that killed at least 129 people.

Malaysian Prime Minister Najib Razak said the weekend summit would address issues of terrorist threats abroad and locally. “These are real concerns to us in the region,” he told a meeting of ASEAN business leaders on Friday. “And we in ASEAN, we are inherently moderate people.”

In September, Malaysian police thwarted a plot to detonate bombs in Kuala Lumpur’s vibrant tourist area of Bukit Bintang, nearby the Petronas Towers. Other recent plots frustrated by Malaysian security forces included plans to raid army camps and seize weapons.

NINE-DASH LINE

The weekend meetings are also expected to spotlight China’s increasingly assertive posture in the South China Sea.

Beijing claims almost the entire South China Sea along with the atolls and islets scattered around its strategic sealanes, which annually carry $5 trillion worth of trade. This clashes with claims by Taiwan and ASEAN members Vietnam, the Philippines, Malaysia and Brunei.

In talks with Philippine President Benigno Aquino on Thursday, Obama demanded China halt land reclamation work that is turning seven reefs in the Spratly archipelago into artificial islands. China is building airfields and other facilities on some of them. Earlier this month, U.S. B-52 bombers flew near the islands, signaling Washington’s determination to challenge Beijing over the disputed sea.

China said it does not want the South China Sea issue to be the focus of the meetings in Kuala Lumpur and a draft of the Chairman’s statement to be issued at the end makes no mention of the recent tensions. It is still being negotiated, however.

Obama has tried to emphasize the U.S. “rebalance” towards the Asia-Pacific with his signature Trans-Pacific Partnership trade deal and strengthening ties with Asian nations facing a more muscular China. But he has been dogged during his swing through the region by concerns over how to counter Islamic State.

He also has issues with Malaysia.

Obama said he will “definitely” raise issues of human rights and corruption when he meets Malaysian Prime Minister Najib Razak on Friday.

“I will do it. I admit I was going to do it anyway but now that I heard it from you, I’m definitely going to do it,” he said in response to a question from a Malaysian student at a town hall at a Kuala Lumpur University shortly after his arrival.

Critics have accused Najib of escalating a crackdown on dissent and free expression after losing the popular vote in the 2013 general election. The prime minister has come under pressure himself after it was revealed in July that nearly $700 million in unexplained deposits were placed into his personal bank accounts. He has denied any wrongdoing but has yet to detail the source and purpose of the money he received.