Saudi Arabia urged its citizens to stay away from public gatherings and universities in Jordan, where riots over fuel price hikes have left one person dead and 71 wounded, state news agency SPA reported.

The kingdom's embassy in Amman "warned Saudi employees and students in Jordan from going to public squares or approaching sites of gatherings and demonstrations," SPA said late on Thursday.

German Chancellor Angela Merkel on Friday called on Cairo to use its influence on Hamas to ease tensions in the Gaza Strip as Egyptian Prime Minister Hisham Qandil visited the violence-wracked area.

"The federal chancellor calls on the Egyptian government to use its influence on Hamas to push it towards a moderation of the violence," Merkel's deputy spokesman Georg Streiter told a regular government news conference.

Tunisian Foreign Minister Rafik Abdessalem will visit Gaza on Saturday, the presidency said, in a statement denouncing Israel's "barbaric aggression" on the Palestinian enclave.

"The presidency of the republic has informed the president of the government in Gaza that a high-level delegation headed by the foreign minister and including the (Tunisian) president's chief of staff will be sent to Gaza tomorrow," it said.

British Foreign Secretary William Hague indicated on Thursday he would decide within days whether to officially recognize the new Syrian opposition after "encouraging" talks with its leaders in London.

Hague said he had pressed Ahmed Moaz al-Khatib and his two deputies, who are on their first visit to a Western capital since a united Syrian opposition was formed last weekend, on the need to be inclusive and to respect human rights.

European Union foreign policy chief Catherine Ashton said Friday that Israel had the right to protect its people against Gaza rocket attacks but urged it to stick to a "proportionate" response.

Deploring the loss of civilian lives on both sides, Ashton said in a statement that "the rocket attacks by Hamas and other factions in Gaza which began this current crisis are totally unacceptable for any government and must stop."

Egyptian Prime Minister Hisham Qandil vowed Friday to intensify Cairo's efforts to secure a truce and end Israel's "aggression" in the Gaza Strip.

"Egypt will not hesitate to intensify its efforts and make sacrifices to stop this aggression and achieve a lasting truce," he said at a press conference in Gaza City's Shifa hospital after seeing some victims from the latest Israeli strike.

Gaza fighters fired rockets at both Jerusalem and Tel Aviv on Friday aiming for the Jewish state's political and commercial hearts, prompting Israel to call up thousands more reservists in readiness for a potential ground war.

The military wing of the Islamist Hamas movement which rules Gaza said it fired the rocket at Jerusalem, the first to strike the outskirts of the Holy City in the history of the Israeli-Palestinian conflict.

Saudi King Abdullah has called for reason and wisdom during a telephone conversation with Egyptian President Mohammed Morsi in which he discussed the latest clashes between Gaza and Israel, state news agency SPA reported.

The monarch, whose country is a heavyweight in the six-nation Gulf Cooperation Council, told Morsi "that things must calm down and reason and wisdom must reign over passionate reactions," SPA said late on Thursday.

Syrian troops bombarded southern districts of Damascus and the outskirts of the capital before dawn, according to the Syrian Observatory for Human Rights and activists on the ground.

Residents in Damascus were kept awake through the night with the sound of explosions rumbling in the capital, they told Agence France Presse.

The Israeli army started calling up 16,000 reservists on Friday, as officials said the Jewish state was preparing for a possible ground offensive into the Gaza Strip.

"They're distributing emergency call-up notices now, the process has started," an army spokeswoman told Agence France Presse.