US Secretary of State Hillary Clinton has pressed Algerian President Abdelaziz Bouteflika to support possible military action in neighbouring Mali, where Islamists control large areas of the north.
Algeria, with its powerful army and intelligence services after years of battling Islamist extremism, is seen by Washington as a key player although it is opposed to having direct military involvement in any intervention.
"We had a in-depth discussion of the region and particularly the situation in Mali," including the "terrorist and drug trafficking threat that is posed to the region and beyond", Clinton told reporters after her talks in Algiers on Monday.
She said they agreed to continue contacts and join regional states, the United Nations, African Union and the Economic Community of West Africa States (ECOWAS) "to determine the most effective approaches we should be taking".
The United States and France have launched a diplomatic offensive to secure Algerian backing for action in Mali after the UN Security Council urged ECOWAS to prepare a military force against al-Qaeda in the Islamic Maghreb (AQIM), which is tightening its grip on the north.
The Security Council called on West African nations to step up such preparations to reconquer territory held by AQIM and other jihadist groups.
Since April, AQIM and Tuareg allies Ansar Dine and the Movement for Oneness and Jihad in West Africa (MUJAO) have imposed Islamist sharia law in parts of Mali that they have effectively partitioned.
Algeria and Mauritania have both called for dialogue in a bid to reach a political solution.
The common influence among the fundamentalist armed groups ruling northern Mali is AQIM, which originated in Algeria and is active regionally, including in Mauritania.
At first Algeria staunchly opposed any military intervention in Mali, fearing a destabilisation of its territory, inhabited by 50,000 Tuaregs, but now it appears it could back an operation as long as it is African in nature and only if its own army is not directly involved.
US sources said Bouteflika did not give a "concrete yes" or "no" to military intervention by ECOWAS.
An Algerian Tuareg chief, MP Mahmud Guemama however has spelled out why he opposed military intervention, in an interview with Elkhabar newspaper published on Monday.
"What the United States and France are asking will cause a lot of problems," he said, warning that such action had "colonial objectives".
"We are more concerned about Algerian towns in the Sahara than northern Mali," he said. "We know how military intention starts but never know the end. Libya was a good example."