Cairo: UN-backed peace talks to end Yemen's civil war resumed on Wednesday after they were suspended by the Yemeni government for three days in protest at a Houthi assault on a military base near the capital Sanaa.
Buttressed by a truce which had been largely holding since April 10, the talks in Kuwait had been inching ahead before their pause and the Houthis said Saudi Arabia had on Saturday released 40 Yemeni prisoners.
UN special envoy to Yemen Ismail Ould Cheikh Ahmed tweeted a picture of delegates representing the main warring sides sitting around a U-shaped table and said talks on Wednesday would focus on cementing the shakey ceasefire.
The Houthis and Yemen's exiled government are trying to broker a peace via talks in Kuwait and ease a humanitarian crisis in the country, where the conflict has drawn in regional powers and killed at least 6,000 people.
A civil war in Yemen escalated when an armed push by the Houthis cast the government into exile on March 26 last year.
Saudi Arabia mustered an alliance of mostly Gulf Arab countries to push the Houthi group back but still appears far from beating the Houthis out of Sanaa.
Human Rights Watch on Wednesday urged participants in the talks to allow international investigations of alleged war crimes by all sides "which have not been investigated nor have resulted in any redress for victims of unlawful attacks".
The group cited air strikes on civilian areas by the Saudi-led coalition backing the government and "indiscriminate" shelling and use of landmines by the Houthis.
"The parties around the negotiating table have an obligation to ensure that the violations against civilians are properly investigated and appropriately punished," HRW deputy Middle East director said in a statement.
Meanwhile, Al Qaeda's Yemen branch remains a powerful force and poses a growing risk to merchant ships in vital waterways nearby despite efforts by Yemeni government forces and their allies to push back the group, a top officer in an international naval force said.
Al Qaeda in the Arabian Peninsula (AQAP) confirmed on Saturday it had withdrawn from the southern Yemeni port of Mukalla - a week after Yemeni government and Emirati soldiers seized the city that was used by the militants to amass a fortune.
Captain William Nault, Chief of Staff with the multi-national Combined Maritime Forces (CMF), told Reuters the gains by government forces were "heartening" and a "setback" for AQAP, but added the group still had capabilities due to the ongoing civil war.
"AQAP has taken advantage of that chaos and moved into the void. In doing so they have gotten stronger," said Nault of CMF, whose mission includes counter-piracy and counter-terrorism in the region.
AQAP still controls the Arabian Sea towns of Zinjibar and Shaqra, about 400 km (250 miles) southwest of Mukalla.
That coastal area is close to the Bab Al Mandab gateway though which nearly four million barrels of oil are shipped daily to Europe, the United States and Asia.
Nault said AQAP had a "stated capability and intent to conduct a maritime terrorist attack", which was something "we look at very hard".
"I would assess that as getting worse over the last year instead of better," he said on a visit to London.
"That threat would be against a soft target meaning an industry ship passing or going in and out of ... the Red Sea towards the eastern end of Yemen."
Yemen has a 1,900-km (1,180 mile) coastline that also juts into the Gulf of Aden and Red Sea, a vast area to police given international navies were already stretched combating Somali piracy in the region, which had been contained in recent years.
AQAP has planned several foiled bombing attempts on Western-bound airliners and claimed credit for the 2015 attack at the Charlie Hebdo magazine offices in Paris.
Al Qaeda bombed the USS Cole warship in October 2000 when it was docked in Aden, killing 17 US sailors. Two years later an Al Qaeda attack damaged a French tanker in the Gulf of Aden.
Nault said there was also the possibility of piracy re-emerging around Yemen, which may involve militants. "That is my concern - will we see a resurgence of piracy-like activity ... it might be something else in that area around Yemen."