monacaでのAndroidアプリのビルド(リリースビルド)で下記のエラーが表示されます。
デバックビルドは正常終了します。
どのあたりを確認すればよいかなどをご教示いただけないでしょうか。

アプリのビルドに失敗しました。次の項目を確認してください。
- Error building project source code
エラーを修正した後で、再度ビルドを行ってください。
Temporary folder: /private/tmp/monaca/59016b08ff2af26c2c7399e6
Downloading project
Download complete
Running for 5.2
plugin add mobi.monaca.plugins.Monaca
No ALTQ support in kernel
ALTQ related functions disabled
pf enabled
Fetching plugin "mobi.monaca.plugins.Monaca" via npm
Installing "mobi.monaca.plugins.Monaca" for android
No ALTQ support in kernel
ALTQ related functions disabled
pf disabled
plugin add cordova-plugin-whitelist@1.0.0
No ALTQ support in kernel
ALTQ related functions disabled
pf enabled
Fetching plugin "cordova-plugin-whitelist@1.0.0" via npm
Installing "cordova-plugin-whitelist" for android
No ALTQ support in kernel
ALTQ related functions disabled
pf disabled
plugin add cordova-plugin-splashscreen@2.1.0
No ALTQ support in kernel
ALTQ related functions disabled
pf enabled
Fetching plugin "cordova-plugin-splashscreen@2.1.0" via npm
Installing "cordova-plugin-splashscreen" for android
No ALTQ support in kernel
ALTQ related functions disabled
pf disabled
Project has 3 plugins.
3 plugins has been installed.
No ALTQ support in kernel
ALTQ related functions disabled
pf enabled
Running command: /private/tmp/monaca/59016b08ff2af26c2c7399e6/android/skeleton/hooks/after_prepare/monaca_enterprise_android.js /private/tmp/monaca/59016b08ff2af26c2c7399e6/android/skeleton
No ALTQ support in kernel
ALTQ related functions disabled
pf disabled
No ALTQ support in kernel
ALTQ related functions disabled
pf enabled
Running command: /private/tmp/monaca/59016b08ff2af26c2c7399e6/android/skeleton/platforms/android/cordova/build --release
ANDROID_HOME=/Applications/android-sdk-macosx
JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.8.0_60.jdk/Contents/Home
Running: /private/tmp/monaca/59016b08ff2af26c2c7399e6/android/skeleton/platforms/android/gradlew cdvBuildRelease -b /private/tmp/monaca/59016b08ff2af26c2c7399e6/android/skeleton/platforms/android/build.gradle -Dorg.gradle.daemon=true

FAILURE: Build failed with an exception.

* Where:
Script '/private/tmp/monaca/59016b08ff2af26c2c7399e6/android/skeleton/platforms/android/CordovaLib/cordova.gradle' line: 25

* What went wrong:
A problem occurred evaluating root project 'android'.
> release-signing.properties: Missing key required "keyAlias"

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

BUILD FAILED

Total time: 1.688 secs

/private/tmp/monaca/59016b08ff2af26c2c7399e6/android/skeleton/platforms/android/cordova/node_modules/q/q.js:126
                    throw e;
                          ^
Error code 1 for command: /private/tmp/monaca/59016b08ff2af26c2c7399e6/android/skeleton/platforms/android/gradlew with args: cdvBuildRelease,-b,/private/tmp/monaca/59016b08ff2af26c2c7399e6/android/skeleton/platforms/android/build.gradle,-Dorg.gradle.daemon=true
ERROR building one of the platforms: Error: /private/tmp/monaca/59016b08ff2af26c2c7399e6/android/skeleton/platforms/android/cordova/build: Command failed with exit code 8
You may not have the required environment or OS to build this project
Error: /private/tmp/monaca/59016b08ff2af26c2c7399e6/android/skeleton/platforms/android/cordova/build: Command failed with exit code 8
    at ChildProcess.whenDone (/data/monaca_build_module/5.2/node_modules/cordova/node_modules/cordova-lib/src/cordova/superspawn.js:139:23)
    at ChildProcess.emit (events.js:98:17)
    at maybeClose (child_process.js:755:16)
    at Process.ChildProcess._handle.onexit (child_process.js:822:5)
Build error: Error building project source code