Pakistan pushed back Saturday against a comment by President Joe Biden in which he called the South Asian country “one of the most dangerous nations in the world.”

Foreign Minister Bilawal Bhutto Zardari said his office would summon the U.S. ambassador for an explanation, and the current prime minister and two former prime ministers rejected the statement as baseless.

Biden was at an informal fundraising dinner at a private residence in Los Angeles on Thursday sponsored by the Democratic Congressional Campaign Committee when he made the comment. Speaking about China and its leader Xi Jinping, he pondered the U.S.’s role in relation to China as it grapples with its positions on Russia, India and Pakistan.

“How do we handle that?” he said, according to a transcript on the White House web page. “How do we handle that relative to what’s going on in Russia? And what I think is maybe one of the most dangerous nations in the world: Pakistan. Nuclear weapons without any cohesion.”

Zardari said in Karachi on Saturday that he discussed the matter with Prime Minister Shahbaz Sharif and it was decided to call the U.S. ambassador to the Foreign Office for an explanation of Biden’s remarks.

“I believe this is exactly the sort of misunderstanding that is created when there is a lack of engagement,” he said, apparently referring to the former government of Imran Khan and its perceived lack of engagement in international diplomacy.

“When Pakistan has nuclear assets we know how to keep them safe and secure, how to protect them as well,” Zardari said.

Sharif in a statement rejected Biden’s remarks calling them factually incorrect and misleading. He said Pakistan over the years has proved itself to be a responsible nuclear state, and its nuclear program is managed through a technically sound command and control system. He pointed to Pakistan’s commitment to global standards including those of the International Atomic Energy Agency.

Sharif said Pakistan and the U.S. have a long history of friendly and mutually beneficial relations. “It is our sincere desire to cooperate with the U.S. to promote regional peace and security,” he said.

Zardari, speaking to reporters, said if there is any question about nuclear weapons security in the region, it should be raised with Pakistan’s nuclear-armed neighbor, India. He said India recently fired a missile that landed accidentally in Pakistan.

Pakistan and India have been arch-rivals since their independence from British rule in 1947. They have bitter relations over the disputed Himalayan region of Kashmir, which is divided between them and claimed by both in its entirety. They fought two of their three wars over Kashmir.

Two former prime minsters took to Twitter to respond to Biden’s comments.

Former premier Nawaz Sharif, the current prime minister’s brother, said Pakistan is a responsible nuclear state that is perfectly capable of safeguarding its national interests while respecting international law and practices. Pakistan became a nuclear state in 1998 when Sharif was in power for the second time.

“Our nuclear program is in no way a threat to any country. Like all independent states, Pakistan reserves the right to protect its autonomy, sovereign statehood and territorial integrity,” he said.

Former premier Imran Khan tweeted that Biden is wrong about the security of Pakistan’s nuclear weapons, saying he knows for a fact that they are secure. “Unlike US which has been involved in wars across the world, when has Pakistan shown aggression especially post-nuclearization ?”

Khan was ousted in April in a no-confidence vote in parliament and has put forward, without giving evidence, a claim that he was ousted as the result of a U.S.-led plot involving Sharif. The U.S. and Sharif deny the accusation.

Zardari noted that Biden’s statement was not made at any formal platform like a news conference but at an informal fundraising dinner. “I don’t believe it negatively impacts the relations between Pakistan and the U.S.,” he said.

Pakistan and the U.S. have been traditional allies but their relations have been bumpy at times. Pakistan served as a front-line state in the U.S.-led war on terror following the 9/11 attacks. But relations soured after U.S. Navy Seals killed al-Qaeda leader and 9/11 mastermind Osama bin Laden at a compound in the garrison city of Abbottabad, not far from Pakistan’s military academy in May 2011.