TRIPOLI, Libya — An American chemistry teacher was shot to death as he was jogging in Benghazi on Thursday, highlighting persistently tenuous security in the eastern Libyan city where the U.S. ambassador was killed last year.

There were no credible claims of responsibility, but suspicion was likely to fall on Islamic militants active in Benghazi. It came days after al-Qaida’s American spokesman called upon Libyans to attack U.S. interests everywhere as revenge for U.S. Special Forces snatching an al-Qaida suspect off the streets of Tripoli in October and whisking him out of the country.

The U.S. State Department identified the teacher as Ronald Thomas Smith II. A Libyan official said Smith was from Texas, and the University of Texas, Austin, said he graduated from the school in 2006 with a master’s degree in chemistry.

Smith, 33, taught chemistry at Benghazi’s International School, a Libyan-owned facility that follows a British curriculum.

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The Austin, Texas, church he attended with his wife, Anita, and their son said Smith had been teaching at the Benghazi school for the past year and a half and that Smith had planned to be home for Christmas.

“Anita and their son had returned to the U.S. and are safe with family. Ronnie, out of a sense of dedication, had stayed in Libya to be with his students through their midterm exams,” Daphne Bamburg, executive pastor of operations at The Austin Stone Community Church said in an email.

A Libyan security official, Ibrahim al-Sharaa, said Smith was shot while jogging near the compound where U.S. Ambassador J. Christopher Stevens and three other Americans were killed by Islamic militants in September 2012.

Adel al-Mansouri, the International School’s chairman of the board, said by telephone from Benghazi that Smith jogged every day in Benghazi “without fear” and was popular with the students. He said Smith had been with the school for just over a year. He said the school, which has 650 pupils ages 4 to 18, had not received any threats because of its Western teachers.

Libyan security forces clashed in Benghazi last month with Ansar al-Shariah, a hard-line Islamist militia blamed for the attack on the diplomatic mission that killed Stevens. Ansar al-Shariah faces a backlash from residents who have marched against it in Benghazi and, in recent days, in its stronghold in the eastern city of Darna.

In an audio speech posted on militant websites late Saturday, al-Qaida’s American spokesman, Adam Gadahn, called the U.S. kidnapping of an al-Qaida suspect from Libya in October a crime of piracy and urged Libyans to attack U.S. interests. Gadahn, a former Osama bin Laden spokesman, said the suspect, Abu Anas al-Libi, had no role in the 1998 bombings of two U.S. embassies in Africa because he had left al-Qaida and formed a new group.

After seizing al-Libi in Tripoli, American special forces detained him on a U.S. warship before bringing him to the U.S. to stand trial.

Smith was active on Twitter, using the handle @ISBchem and calling himself “Libya’s best friend.” He had humorous exchanges with students and noted “There is one thing Libyans are good at: making foreigners feel like family.”

He frequently commented on the difficult situation in the city and mocking Libyan habits. He also didn’t shy from black humor about the rampant militias in the city.

“I understand I teach at a school of rich kids, so if (and when) I’m kidnapped by Ansar al-Sharia, who’s gonna pay the ransom?” he tweeted.