Tunis, Tunisia — Tunisian police shot dead an Islamist militant in Tunis and arrested several suspected militants on Sunday, an official and witnesses said, as the government grapples with growing security and political crises.

There has been a surge in Islamist militant attacks over the past two weeks in the North African country, and on Friday security forces launched heavy air and artillery strikes on militant hideouts near the Algerian border.

The nation is also mired in political turmoil as the secular opposition tries to oust the moderate Islamist-led government.

Tens of thousands of Tunisians came out in a show of force for the ruling Ennahda party on Saturday. The opposition has pledged to overtake those numbers in a rally later on Sunday.

Interior ministry official Lotfi Hidouri said the shooting on Sunday took place when police raided a house where militants were hiding weapons in the Kabaria district of Tunis. "The police killed a terrorist and arrested five others," he said.

Witnesses said police also arrested several hardline Salafists suspected of ties militant groups, in the town of Sbitla, north of the capital.

One witness said dozens of Salafists then gathered at the police headquarters in Sbitla to protest against the arrests and that the police fired in the air to disperse them.

Over the past week, a roadside explosive device and a car bomb have targeted security forces in Tunis, the first such attacks to hit the capital. No one was hurt.

"MODEL" IN CRISIS

Tunisia, once considered a model among fledgling "Arab Spring" democracies, is facing its worst crisis since Tunisians toppled autocrat Zine el-Abidine Ben Ali and set off a wave of uprisings across the region.

The opposition, angered by the assassination of two of its figures and emboldened by Egypt's army-backed ousting of its elected Islamist president, is seeking to topple the government.

It has accused Ennahda of being linked or tolerating Islamist militant attacks. The party denies this and has denounced recent attacks as terrorism.

Tens of thousands of Tunisians crowded into the Kasbah Square on Saturday in a show of force for Ennahda, shouting "No to coups, yes to elections!" It was one of the biggest demonstrations since the 2011 revolt.

As well as the rally later on Sunday, the opposition is planning a protest on Wednesday to mark the six-month anniversary of the assassination of leftist politician Chokri Belaid.

The air and artillery strikes by security forces, in the Mount Chaambi area near the Algerian border, were launched after militants killed eight soldiers last week in one of the deadliest attacks on security forces in decades.

State Tataouin radio and other local media reported on Sunday that Tunisian forces had killed 10 militants in Chaambi and arrested three others.

The interior ministry declined to comment and defense ministry officials were not available.