“Al Qaeda’s Yemen arm said on Friday it was behind coordinated attacks on security offices in the Arabian peninsula state in which four people were killed, and threatened more strikes on Yemeni targets.

Gunmen on motorcycles stormed police and intelligence offices in south Yemen and opened fire on July 14, part of a series of recent al Qaeda attacks in response to a government crackdown.

“Suspected Al-Qaeda gunmen launched simultaneous attacks Wednesday on the intelligence and security services headquarters in the south Yemen town of Zinjibar, killing three policemen and wounding 11, a security official said.

Two gunmen were killed and one wounded in the clashes, the official added.

He said that around 20 gunmen carried out the attacks, and that Al-Qaeda was believed to be responsible.

“The U.S. Office of Naval Intelligence said on its website that ships in the Red Sea, the strategic Bab al-Mandab strait between Yemen and Djibouti, and the Gulf of Aden along Yemen’s coast were at the greatest risk.

‘Information suggests that al Qaeda remains interested in maritime attacks in the Bab al-Mandab Strait, Red Sea, and the Gulf of Aden along the coast of Yemen,’ the office said in a statement, citing an advisory by the U.S. Department of Transportation.

‘Although it is unclear how they would proceed, it may be similar in nature to the attacks against the USS Cole in October 2000 and the M/V Limburg in October 2002 where a small to mid-size boat laden with explosives was detonated,’ it added.

“Yemen has beefed up security around oil and maritime installations for fear of retaliation by Al-Qaeda after several strikes against the jihadist network, the interior ministry said on Wednesday.

‘Yemeni authorities have increased security measures around oil and maritime installations, in addition to securing the routes of oil tankers,’ the ministry website said.

‘Firm orders have been given to security bodies and the coast guard to up their alert levels in order to counter any possible terror attack by Al-Qaeda elements,’ it added.

It said that attacks could take place ‘in retaliation to the qualitative and severe strikes that targeted terror hideouts in several provinces.’

“A senior operative of the al-Qaida network in Yemen – the group that claimed responsibility for the failed Christmas Day attack on an American passenger jet over Detroit – has threatened more attacks on the United States.

The U.S. has become increasingly worried about militants based in Yemen since al-Qaida groups there and in Saudi Arabia merged last year to become al-Qaida in the Arabian. The group has openly targeted U.S. and other Western interests in Yemen, and – as demonstrated by the Dec. 25 attack – abroad.