The so-called "Five Eyes" nations agreed on a lot coming out of their security summit in London this week, but didn't end up with concrete plans for two major challenges: the security threat posed by Chinese tech firm Huawei, and the stalemate over how to deal with thousands of foreign-born Islamic State fighters held in Syria.

The five English-speaking member nations that comprise the intelligence-sharing alliance agreed on “emerging threats” including child exploitation, web encryption, extremist recruitment online, and terrorism. They agreed the exploitation of children online must be addressed more effectively, that violent extremists must not be allowed to exploit the internet, that tech firm encryption designed to keep law enforcement out could threaten public safety, and that they must remain vigilant against ISIS.

And the countries committed to combating foreign election interference, ensuring drones aren’t misused, improving information sharing, and cooperating on cyber threats.

“The Five Eyes partnership is vital. Throughout this week, we have had substantive, frank, and positive discussions surrounding our shared duty to protect public safety,” said Attorney General William Barr, who represented the United States in the summit with officials from the United Kingdom, Australia, Canada, and New Zealand.

But comprehensive solutions for dealing with ISIS and Huawei appeared elusive.

The alliance pledged to deal with ISIS detainees, noting the collapse of the caliphate and recognizing that “some of its members continue to pose a threat both in the region and more widely, whilst others are detained and best efforts must be made to bring them to justice.” There were some specifics: capacity building through the United Nations and the Counter Terrorism Forum; information sharing through Interpol and other databases to assist with terrorist identification; and the promotion of Battlefield Evidence best practices for investigations and cases.

But these efforts did not specifically address what to do with the thousands of foreign born ISIS fighters held in Iraq and Syria. Earlier this year, President Trump tweeted that the U.S. was asking countries like the U.K. to “to take back over 800 ISIS fighters that we captured in Syria and put them on trial.”

But most European countries have been hesitant to do so, with the U.K., for instance, often working to strip fighters of citizenship instead. Countries such as France outsourced the problem to the Iraqi court system, yet expressed dismay when Iraqi judges sentenced many of the convicted terrorists to death.

The pledge released by the member nations also stressed “the importance that supply chains in the 5G network should be trusted and reliable to protect it from unauthorized access” in what may have been a reference to Huawei. But no plan was presented for bridging the gap between the U.S. and its allies on this issue. Fifth Generation — or “5G” — cellular technology is a huge innovation, but the U.S. widely suspects that Huawei, a global leader in the arena, is working with China's surveillance state to give it access to hardware and networks around the world.

Trump's executive order from May noted that foreign adversaries are exploiting vulnerabilities and he aimed to limit the use of technology from firms like Huawei. Secretary of State Mike Pompeo warned Five Eyes nations about Huawei earlier this year, saying, “If a country adopts this and puts it in some of their critical information systems, we won’t be able to share information with them, we won’t be able to work alongside them.”

But, aside from Australia, other Five Eyes countries haven’t seen the threat as grave and have resisted U.S.-style bans on Huawei technology. As one example, former U.K. Prime Minister Theresa May initially agreed to allow Huawei access to parts of Britain’s 5G network, but that decision was put on hold following U.S. pressure. However, the U.K.’s largest phone company, which uses some Huawei components, recently began providing 5G services across the country, and the U.K.’s digital minister recently said that U.K. companies should make their own decisions.

The ongoing disagreements over Huawei and ISIS will likely be a topic of further discussion when Secretary of State Mike Pompeo visits Australia in the coming week.