More than 50 people have been killed in Uzbekistan this year in violence the Uzbek government blames on Islamic extremists.
Both the Kazakh and Kyrgyz governments say they are doing, or will do, something to increase security.
Speaking at a press conference, Karimov once again blamed the Islamic group Hizb-ut Tahrir for the recent acts of violence. But he also pointed a finger at neighboring countries for allowing that group and others to operate freely.
"How can we fight when we don't have borders and [members of] [Hizb-ut Tahrir] are freely able to go to neighboring territories, train, live and operate there freely, conduct their activities and the next day they commit their wild acts?" Karimov said.
Hizb-ut Tahrir, for its part, has denied involvement, saying it rejects violence as a means to its goal of establishing an Islamic caliphate in Central Asia.
Kazakhstan has recently come into focus as a possible haven for militants.
Uzbek authorities say one of the suicide bombers blamed in a July attack on the U.S. and Israeli embassies in Tashkent came from Kazakhstan. Russian investigators have also charged that Kazakhs were present during the recent Beslan hostage crisis.
Kazakh President Nursultan Nazarbaev last week made clear his country would spend more money on security.
"We must pay the utmost attention to strengthening our country's defense and security," Nazarbaev said. "The people should remember that we must spend more money now on our safety, on strengthening our defense, on the fight against drug trafficking, on preventive measures against the spread of terrorism."
Vladimir Bozhko, the first deputy chairman of Kazakhstan's National Security Committee (KNB), admits that Kazakhstan has been used as a transit route for what he called "terrorists" from Uzbekistan.
Kyrgyz officials also admit there is a problem. They have been warning for nearly a year that Islamic groups are actively recruiting in Kyrgyzstan.
Unlike Kazakhstan, however, Kyrgyzstan seems to be putting its trust in foreign support. Both the U.S.-led antiterrorism coalition and Russia have military bases in Kyrgyzstan, and it is to these outsiders that Kyrgyzstan has turned for its security guarantees.
"When the USA was faced [with the issue of fighting international terrorism], it established an antiterrorist coalition," Abdil Segizbaev, Kyrgyzstan's presidential press secretary, said during a ceremony last weekend at a ceremony marking the 2001 attacks on the United States. "We [contributed to that coalition], providing them an air base at the airport of Manas. Besides that, a Russian air base was established at the town of Kant. Why are we doing all those things? In order to provide security in the country."
Correspondents say that neither of those bases is actively engaged in pursuing radical Central Asian movements and say they doubt that international support will be enough.
That could leave the Central Asian states to chart their own course toward better security.
(The Uzbek, Kazakh, and Kyrgyz services contributed to this report)