Saudi Arabia, a long-time ally of the US, had also declared their support for Saturday's strikes on Syria by the US, UK and France, although the king did not mention this during his speech.
On Libya, the Arab leaders will stress their commitment to supporting the unity and sovereignty and the territorial integrity of the North African country, rejecting any interference in its affairs.
Delegates pledged to support the Palestinians, who want East Jerusalem to be the capital of a future Palestinian state.
Sunday's meeting will be the first Arab League summit since Egypt, Saudi Arabia, the United Arab Emirates and Bahrain cut their diplomatic ties with Qatar 10 months ago and the first since President Donald Trump announced his decision to relocate the USA embassy from Tel Aviv to Jerusalem.
Jerusalem remains at the heart of the Middle East conflict, with Palestinians hoping that East Jerusalem - occupied by Israel since 1967 - might eventually serve as the capital of a Palestinian state.
The summit, held at Dhahran's King Abdulaziz Center for World Culture, brings together the kings, presidents and leaders of 17 Arab countries.
Opening the 29th Arab League summit, the king criticised the United States decision to transfer its embassy in Israel to Jerusalem and described "terrorism" as the biggest challenge facing Arab leaders.
The Qatari delegation is being headed by Doha's permanent representative to the Arab League, Saif bin Muqaddam al-Buainain, Qatar's state news agency said, without elaborating.
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He also conceded it was sweet to triumph in a country where some critics claimed his purist principles couldn't flourish. He won three league titles with Barcelona and twice lifted the Champions League trophy during his Camp Nou reign.
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You either jump ship and start a new relationship or move forward and try to work through it. "We work every day on us". He didn't really say yes or no, but at that time they were still working on things. "We haven't yet jumped ship".
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The PDP thanked Prime Minister Narendra Modi, BJP president Amit Shah and Ram Madhav for helping resolve the issue. According to police charges, the minor from the nomad Bakerwal community was kidnapped on January 10.
King Salman expressed his strong condemnation to the "Iranian-allied" Houthi militants' attacks on different cities of Saudi Arabia.
"We reiterate our rejection of the United States decision on Jerusalem", Salman said adding "East Jerusalem is an integral part of the Palestinian territories".
Regional powerhouses Saudi Arabia and Iran have been locked in a decades-long struggle for supremacy that is being waged in proxy wars in several countries, including Yemen and Syria.
The King welcomed the statement issued by the Security Council, which strongly condemned the launching of Iran-made ballistic missiles by the Houthi militia on Saudi cities.
Arab ministers at a preliminary meeting in Riyadh on Thursday focused heavily on blocking the embassy move, unanimously condemning Trump's decision.
The summit also issued the "Dhahran Declaration" which brought the viewpoint of the Arab leaders on the issues related to the region.
Ahmed Aboul Gheit, secretary-general of the Arab League, said that the serious crises in the region facilitated foreign interference.