Yemen has begun a clampdown on western media, arresting and deporting four foreign journalists who had been covering government attacks on protesters in which seven people were killed over the weekend.

The journalists were taken from their house in Sana'a shortly after dawn, when police from the interior ministry forced their way into the building and confiscated their mobile phones and passports.

They were held for three hours at the immigration centre in Sana'a before being told to pack their bags and leave the country immediately.

The four, all young freelancers for American newspapers, included two US citizens – Haley Sweetland Edwards, who writes for the Los Angeles Times, and Joshua Maricich, a photographer – and two Britons – Portia Walker, who writes for the Washington Post, and Oliver Holmes, who writes for the Wall Street Journal and Time magazine.

Speaking from Sana'a airport, Holmes, 24, said he had not been given an explanation for the deportation but suspected it was because of their recent reporting of the attacks on protesters.

With only a handful of foreign journalists remaining in the country, analysts are worried the regime may be planning a severe crackdown on protesters. "The deportation of these journalists along with the increasingly violent assaults on protesters are extremely worrying. I think a Gaddafi-style clampdown could be imminent," said Abdullah Al-Faqih, a professor of politics at Sana'a University. There have been daily anti-government demonstrations in Sana'a and other cities in the period since the former Egyptian president Hosni Mubarak was ousted on 11 February. So far 40 people have been killed in the unrest, according to international rights groups.

Fresh violence erupted on Monday when the governor of Marib, an eastern desert province, was stabbed in the neck while trying to disperse anti-government protesters, a local official said. Governor Ahmed Naji al-Zaid was stabbed by a group of armed men who attacked his convoy. He is said to be in a critical condition.

In Jowf, north-east of Sana'a, 40 protesters trying to storm the government headquarters were wounded when security forces and pro-regime loyalists guarding the building opened fire.

Monday's fighting followed a dramatic weekend in the capital. Seven people were killed when riot police with water cannon, teargas, and rubber bullets fired on anti-government protesters near Sana'a University.

Sami Zaid, a doctor from Islamic Relief, said plain-clothes civilians also took part in the shooting. There have also been reports of Yemeni security forces abducting injured protesters from hospital for interrogation.

"Two wounded individuals at the Saudi German hospital were arrested on Saturday by national security men who arrived in civilian clothing," said Abdulrahman Barman, a Yemeni human rights activist and a legal representative of the protesters. "The hospital is morally and professionally responsible for their arrest. They shouldn't allow any patient to be removed from the premises illegally," he said.