U.N.-Arab League Syria peace envoy Lakhdar Brahimi is on the verge of quitting amid growing frustration at deadlocked international efforts to end the worsening conflict, diplomats said Wednesday.

Brahimi, who took over from former U.N. leader Kofi Annan in August last year, is "itching to resign but being persuaded to hang on for a few more days," said one U.N. Security Council diplomat.

Two bombs in central Damascus killed one person and wounded several others on Wednesday, a monitoring group said, a day after another bombing killed 13 people in the Syrian capital.

One bomb detonated near a police station on the Khaled bin al-Walid main road, killing one, and the second went off in Bab al-Musalla square, the Syrian Observatory for Human Rights said.

Gunmen pressed their siege of two Libyan ministries on Wednesday, leaving the authorities in a dilemma of whether to risk a bloody confrontation or reinforce the image of a helpless state by negotiating patiently.

They have encircled the foreign ministry since Sunday and the justice ministry since Tuesday, demanding the sacking of former officials from the ousted regime of Moammar Gadhafi.

Tunisian troops clashed on Wednesday with around 50 armed jihadists in the remote Mount Chaambi border region, a security source said, the first such operation since the revolution in January 2011.

"The group consists of more than 50 Salafi jihadists," the source told Agence France Presse, adding that they were well armed and some were veteran Islamist militants who had come from northern Mali.

Kuwait's lower court on Wednesday sentenced a Saudi man to five years in jail for insulting the emir on Twitter, a human rights activist said.

The court passed the sentence on Abdulaziz al-Mutairi in absentia, as his whereabouts are currently unknown, the director of the Kuwait Society for Human Rights, Mohammad al-Humaidi, told AFP.

Japan and Saudi Arabia condemned "grave" human rights violations by Syria's regime which they said has lost its "legitimacy", in a joint statement on Wednesday after a meeting of top officials.

Japan's Prime Minister Shinzo Abe arrived Tuesday in the OPEC kingpin, where he met with Crown Prince and Defense Minister Salman bin Abdulaziz.

Syria's President Bashar Assad made a rare public visit on Wednesday to an electrical plant in central Damascus to mark Labor Day, the presidency's official Facebook page said.

"President Assad is now visiting the Umayyad electrical plant in Tishreen Garden in Damascus and congratulates its workers and Syria's workers on their holiday," the Facebook page said.

Prime Minister Benjamin Netanyahu said Wednesday that an Israeli withdrawal would not bring peace with the Palestinians because the heart of the conflict was their refusal to recognize Israel as a Jewish state.

His remarks came a day after the Arab League announced moves to revive and modify its 2002 peace initiative, drawing praise from Washington and Israel's chief peace negotiator Tzipi Livni but no official response from the Israeli government.

Two bomb attacks in Iraq on Wednesday killed eight people, including four anti-Qaida fighters who died when a suicide bomber struck as they gathered to collect their salaries, officials said.

The bomber, who was on foot, detonated explosives at a police station in Fallujah, west of Baghdad, as the militiamen, known as Sahwa, gathered near a police station, police Lieutenant Colonel Khaled Yassir al-Jumaili said.

Israel will keep refusing to negotiate on the basis of a total withdrawal from land it seized during the 1967 Six-Day War, a minister said Wednesday after the Arab League modified its peace plan.

"If Israel agrees to come to the negotiating table while accepting in advance that talks would be held on the basis of the 1967 lines, there wouldn't be very much to negotiate about," said Gilad Erdan, a minister in the security cabinet and considered close to Prime Minister Benjamin Netanyahu.