A blast ripped through a bus carrying Lebanese Shiite pilgrims in Damascus on Sunday, killing at least nine people, a monitor said, in an attack claimed by al-Qaida's Syrian branch.

The Syrian Observatory for Human Rights said at least 20 people were wounded in the explosion near Souq al-Hamadiyeh district, and that six of the dead were Lebanese citizens.

Justice Minister Ashraf Rifi on Friday asked the public prosecution to seek the arrest and penalization of those who opened fire in celebration of a much-anticipated speech by Hizbullah chief Sayyed Hassan Nasrallah.

The celebratory gunshots and rocket-propelled grenades sparked panic and damaged cars and the facades of some buildings in the capital Beirut and its suburbs.

Spain and Israel have agreed to carry out a joint investigation on the death of a Spanish U.N. peacekeeper who was killed in Lebanon during Israeli shelling near the border, Madrid said on Friday.

The soldier was killed on Wednesday when the Israeli military shelled border areas in southern Lebanon following a Hizbullah attack that left two Israeli soldiers dead, Spanish authorities said.

Hizbullah chief Sayyed Hassan Nasrallah declared on Friday that the party no longer recognizes the rules of engagement with Israel, saying that it has the right to respond to an Israeli attack in any way or time it deems fit.

He said: “The resistance no longer recognizes the rules of engagement and it has the right to respond to the enemy at any time or place.”

Saudi Arabia's new King Salman has tightened his hold on power, firing two sons of his predecessor and replacing the heads of intelligence and other key agencies in a sweeping shakeup.

The appointments, which analysts said supported signs the kingdom will chart a steady course on foreign and oil policy, came a week after Salman, 79, took the throne following the death of King Abdullah.

Israel on Thursday buried two soldiers killed in a Hizbullah missile strike that triggered Israeli fire on southern Lebanon, raising tensions between the bitter enemies to their highest in years.

But the Israeli-Lebanese border was calm, and Israeli officials played down the threat of a new war with the Iran-backed group.

The U.N. Security Council condemned on Wednesday the death of a Spanish U.N. peacekeeper during the Israeli military's exchange of fire with Hizbullah in a disputed border area.

The Council condemned his death in the strongest terms and offered its deepest sympathies.

The United States on Wednesday condemned Hizbullah's deadly operation in the Israeli-occupied Shebaa Farms as an "act of violence," urging all parties to refrain from actions that could escalate the situation, as France requested an urgent meeting of the U.N. Security Council.

U.S. State Department spokesperson Jen Psaki said that Washington did not want "an escalation of the situation."

A U.N. peacekeeper from Spain was killed on Wednesday when the Israeli military shelled border areas following a Hizbullah attack that left two Israeli soldiers dead.

A 36-year-old corporal "died this morning during incidents between Hizbullah and the Israeli army in the area of responsibility of the Spanish contingent", the Spanish defense ministry said in a statement.

Two Israeli soldiers were killed and seven wounded on Wednesday in a Hizbullah attack on a military convoy in the occupied Shebaa Farms.

The Israeli army announced that two of its troops were killed, while a spokesman said seven Israeli soldiers were “lightly-to-moderately wounded” in the attack.