TUNIS (Reuters) - Tunisian police shot dead an Islamist militant in Tunis and two soldiers were killed in a blast near the Algerian border on Sunday, as the government grappled 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 in the Mount Chaambi area near the Algerian border.
At the same time, the secular opposition, angered by the assassination of two of its leading members and emboldened by Egypt's army-backed ousting of its elected Islamist president, is seeking to topple its own moderate Islamist-led government.
Tens of thousands of Tunisians came out in a show of force for the ruling Ennahda party on Saturday, shouting "No to coups, yes to elections.
On Sunday night, the opposition held a rival rally that drew more than 20,000, the largest protest since it began launching daily demonstrations last week.
Earlier on Sunday, two soldiers were killed and six others were wounded by a landmine that hit their tank as they searched an area in Mount Chaambi, where militants killed eight soldiers last week in the deadliest attack on Tunisian forces in decades.
In the capital Tunis, Interior Ministry official Lotfi Hidouri said police raided a house where militants were hiding weapons in the Kabaria district. "The police killed a terrorist and arrested five others," he said.
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.
Once considered a model among fledgling "Arab Spring" democracies, Tunisia is facing its worst crisis since protesters toppled Ben Ali and sparked a wave of revolts across the region.
The opposition has accused Ennahda of being linked to or tolerating Islamist militant attacks. The party denies that and has stepped up recent efforts to crack down. It denounced recent attacks as terrorism.
Demonstrations swept Tunisia after the assassination of Mohamed Brahmi, a member of the Arab nationalist Popular Front party, on July 25. The killing followed the assassination of party leader Chokri Belaid in February.
In Tunis's Bardo square on Sunday, opposition protesters chanted slogans against Ennahda and participants said their rally was a more legitimate expression of popular will.
They criticised Ennahda for renting buses to bring protesters to Kasbah Square on Saturday and providing meals to the crowds, which the party said topped 150,000 people.
"With our large crowds we say to Ennahda that we are able to shake your government, which is more dictatorial than Ben Ali, and we will sweep you out of Tunis," said Amal, waving a red Tunisian flag.
"We have gathered in our tens of thousands tonight without using buses or food ... and on Wednesday we will see the protest that ends Islamist rule."
The opposition is planning a mass protest on Wednesday to mark the six-month anniversary of Belaid's assassination.
Amid rising pressure for the government to resign, security forces are trying to step up the fight against Islamist militants.
A Salafist militant on Sunday fired on police who tried to stop his car as he drove near the southeastern town of Ben Guerden, near the Libyan border, state television reported.
The channel said weapons were found inside the vehicle and the man was believed to be one of a large group of prisoners granted amnesty by a previous transition government in the days after Ben Ali was ousted.
Prime Minister Ali Larayedh told journalists on Sunday a man suspected of ties to the Belaid assassination was captured by security forces. He called on militants to turn themselves in.
"I call on the terrorists being hunted by security forces to turn themselves in. There is no future in terrorism," he said, speaking outside the Interior Ministry, where he had been meeting officials. (Writing by Erika Solomon; Editing by Sonya Hepinstall and Doina Chiacu)