A senior Pakistani official said Friday the government is serious about fighting Islamic militants, after authorities said they had rounded up 220 suspects as a military operation proceeded in a volatile tribal region.

But critics claimed the offensive along the Afghan border has been largely ineffective because many of those targeted had already fled and no leading militant chiefs were captured.

North West Frontier Province Gov. Owais Ahmed Ghani defended the deployment of hundreds of security forces in Khyber agency, where authorities say they have also banned three local militant groups.

“The state is very serious” in fighting militants and the government plans to launch crackdowns against militants in other parts of the province, Ghani told reporters, without elaborating.

The Ministry of Interior said it has so far arrested 92 “criminals” and seized large caches of arms and ammunition in Khyber. Another 128 suspects have been arrested and drugs and weapons seized separately in the nearby city of Peshawar.

The government said it launched the operation as Peshawar, the main city in the volatile northwest, was under threat from militants. Khyber is also a supply route to U.S. and NATO forces in Afghanistan.

Former lawmaker Lateef Afridi, who is a Khyber native and a senior figure in the Awami National Party that rules the province, contended that security forces were not serious in going after militant leaders. He alleged that only “common people” were arrested.

Another senior politician in the province said supporters of the Lashkar-e-Islam and Ansarul Islam groups fled to the remote Tirah valley ahead of the crackdown. The groups are accused of trying to impose their own Taliban-style Islamic rules in Khyber.

The politician requested anonymity as his party is a member of the ruling coalition and does not want to publicly criticize the government.

Despite the operation, the two groups have been fighting each other this week in the valley, reportedly killing dozens.

Nevertheless, Ghani maintained that the operation in Khyber was “going on successfully” and that the government had a program for tackling the province’s law and order problems.

“I can say confidently that the targets we had laid down are gradually being achieved,” he said.