We warned a year ago that Yemen was on the brink of sectarian war. It is starting to look like it is going over the brink. From AP, May 2:

Motorcycle bomb explodes outside Yemen mosque, killing 18
SAN'A — A bomb rigged to a motorcycle blew up amid a crowd of worshippers leaving Friday prayers at a mosque in a rebel stronghold of northern Yemen, killing at least 18 people and wounding about four dozen, officials said.

The attack occurred in Saada, a city in a mountainous Shiite Muslim area on the border with Saudi Arabia where a rebellion by members of the al-Zaydi sect erupted in 2004. Thousands have died in violence between the rebels and the government of this predominantly Sunni country.

Both sides blamed each other for the attack in Saada, where officials said most of the 18 dead and approximately 45 injured were worshippers filing out of the Bin Salman mosque.

Mohammed Abdel Bari said he was inside the mosque when he heard a strong explosion. "I saw crowds of people and two charred vehicles. I saw scores of people laying on the ground," he said.

Government officials blamed the bombing on rebel leader Abdel-Malek al-Hawthi and said six people had been arrested in Saada.

"Those who carried out this ugly crime are terrorists and criminals linked to the terrorist Abdel-Malek al-Hawthi," an Interior Ministry statement said.

Al-Hawthi denied involvement and charged that senior army officers staged the attack to stoke tensions.

"We denounce and condemn this incident," he told The Associated Press by telephone. "We have nothing to do with this attack whatsoever."

The rebels say the government is corrupt and too closely allied with the West. The government has charged al-Hawthi with sedition, forming an illegal armed group and inciting anti-American sentiment.

Many officials in Sunni-led Saudi Arabia and in Yemen's government suspect Iran and Libya support al-Hawthi. Sunni governments in the region suspect Shiite Iran is trying to increase its influence by supporting Shiite groups like the militias in Iraq and Hezbollah in Lebanon.

Al-Hawthi denies that his group, known as the Young Faithful Believers, receives funds from Iran.

Yemen is a key U.S. ally in the Middle East, but it also is the ancestral homeland of Osama bin Laden's family and al-Qaida loyalists are active in the country.

Recently there have been a series of attacks in Yemen targeting foreigners. But car bombings and attacks on mosques are rare.

The mosque attack came a day after Yemen's military announced the killing of seven soldiers and blamed Saada rebels. More government troops were expected to be deployed to the area even before Friday's attack.

We assume the targeted mosque was Sunni, although this account (and others from the major agencies) failed to make that clear.

See our last post on Yemen.