KABUL, Afghanistan (AP) – Despite a rise in insurgent violence this spring, Secretary of Defense Gates said Sunday he is convinced that American and NATO forces are making steady progress against the Taliban.

“I think actually things are slowly, cautiously headed in the right direction,” Mr. Gates told reporters. “I’m concerned to keep it moving that way.”

He spoke during a flight to the Afghan capital from Singapore, where he attended a security conference. The Pentagon chief had urged Asian nations to provide more troops or other forms of support for Afghanistan.

For months, Mr. Gates has expressed concern about possible reversals in Afghanistan, which still lacks a self-sustaining military and suffers from the unmet expectations of building an effective central government.

In the interview Sunday, Mr. Gates appeared more optimistic, though still skeptical, about maintaining momentum against the Taliban and overcoming the economic and political obstacles that have bedeviled Afghanistan for decades.

Mr. Gates arrived in an Air Force C-17 cargo plane for his second visit to Afghanistan since taking over at the Defense Department last December.

On his first trip, in January, he worried about Taliban incursions from havens inside neighboring Pakistan and said it appeared the Taliban were gearing up for a spring offensive.

Since then, levels of violence in Afghanistan have risen but the Taliban offensive has gained little of a foothold.

A senior defense official traveling with Gates told reporters it was believed the Taliban had intended to target Kandahar, the southern city that was a stronghold before American forces invaded in October 2001, and to try to isolate certain portions of the main Afghan highway known as the ring road. The official discussed American analysis of recent trends in the conflict on condition he not be named.

Mr. Gates did not rule out that the Taliban could intensify their attacks this summer. Other officials have asserted that the radical Islamic movement is beginning to gain assistance from neighboring Iran, including weapons such as the new, more sophisticated roadside bomb known as an explosively formed projectile, or EFP.

In contrast to Mr. Gates’ moderately optimistic comments about progress, a Washington think tank said in a March study the overall situation has deteriorated. The Center for Strategic and International Studies concluded, on the basis of interviews with hundreds of Afghans, that they are more insecure now than in 2005 when the center did a similar study.

The study also said conditions had deteriorated in all important areas – including governance and justice – except for the economy and women’s rights.

“Restoring progress in Afghanistan requires dramatic changes,” the study concluded. “If a critical mass of Afghans experiences positive change, the negative trends are reversible. The year 2007 is the breaking point.”

Mr. Gates said on his way to Kabul that he felt compelled to visit now so he could meet with Army Gen. Dan McNeill, the commander of NATO’s International Security Assistance Force, and American Ambassador William Wood. Both men have assumed their posts since Mr. Gates visited in January.

“I’m looking forward to getting their assessment of how they think things are going,” Mr. Gates said, “both in terms of military action against the Taliban, but also the economic development and reconstruction.”

He said he also would meet with President Hamid Karzai.

“I want to talk to the ambassador and the commanders about coordination (to) see if they are satisfied,” he added. “One of my concerns is that we have 42 countries and 12 NGOs (nongovernmental organizations) out here and I want to find out if there’s anyone really creating an overall strategy or coordinating their activities so that we can make the best possible use of the resources.”

Mr. Gates said he planned to tell Wood and the U.S. commanders about his conversations in Singapore, where he asked some Asian nations that already have military forces or civilian support teams in Afghanistan to extend their stay or to increase their contributions. He did not mention any countries by name.

America has more than 24,000 troops in Afghanistan.

Earlier Sunday, before leaving Singapore, Mr. Gates cautioned Turkey against sending troops into northern Iraq, as it has threatened, to hunt down Kurdish rebels it accuses of carrying out terrorist raids inside Turkey.

“We hope there would not be a unilateral military action across the border into Iraq,” Mr. Gates told a news conference.

Mr. Gates said he sympathized with the Turks’ concern about cross-border raids by Kurdish rebels.

“The Turks have a genuine concern with Kurdish terrorism that takes place on Turkish soil,” he said. “So one can understand their frustration and unhappiness over this. Several hundred Turks lose their lives each year, and we have been working with the Turks to try to help them get control of this problem on Turkish soil.”

Tensions have heightened in recent weeks in northern Iraq as Turkey has built up its military forces on Iraq’s border, a move clearly meant to pressure Iraq to rein in the rebels of the Kurdistan Workers’ Party, or PKK, separatists who launch raids into southeast Turkey’s Kurdish region from hideouts in Iraq.

Turkey’s political and military leaders have been debating whether to try to root out those bases, and perhaps set up a buffer zone across the frontier as the Turkish army has done in the past.

Turks accuse Iraqi Kurds, who once fought alongside the Turkish soldiers against the PKK in Iraq, of supporting the separatist rebels and worry that the war in Iraq could lead to the country’s disintegration and the creation of a Kurdish state in the north.