diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index d80d483..17e4f88 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -26,7 +26,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        ruby: ['3.0', 3.1, 3.2, ruby-head, jruby]
+        ruby: ['3.0', 3.1, 3.2, 3.3, ruby-head, jruby]
     steps:
       - name: Clone repository
         uses: actions/checkout@v3
@@ -40,6 +40,6 @@ jobs:
         run: ruby --version; bundle exec rspec spec || $ALLOW_FAILURES
       - name: Coveralls GitHub Action
         uses: coverallsapp/github-action@v2
-        if: "matrix.ruby == '3.2'"
+        if: "matrix.ruby == '3.3'"
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
diff --git a/lib/rdf/n3/reader.rb b/lib/rdf/n3/reader.rb
index 8149ed0..38cc1ee 100644
--- a/lib/rdf/n3/reader.rb
+++ b/lib/rdf/n3/reader.rb
@@ -826,6 +826,8 @@ def ns(prefix = nil, suffix = nil)
       namespace(nil, iri("#{base_uri}#")) if prefix.nil? && !prefix(nil)
 
       base = prefix(prefix).to_s
+      suffix = suffix.gsub(PN_LOCAL_ESC) {|esc| esc[1]} if
+        suffix.match?(PN_LOCAL_ESC)
       suffix = suffix.to_s.sub(/^\#/, "") if base.index("#")
       iri(base + suffix.to_s)
     end
diff --git a/rdf-n3.gemspec b/rdf-n3.gemspec
index 18f99b0..be11b5d 100755
--- a/rdf-n3.gemspec
+++ b/rdf-n3.gemspec
@@ -28,11 +28,12 @@ Gem::Specification.new do |gem|
   gem.required_ruby_version = '>= 3.0'
   gem.requirements          = []
 
-  gem.add_dependency             'ebnf',            '~> 2.5'
-  gem.add_dependency             'rdf',             '~> 3.3'
-  gem.add_dependency             'sparql',          '~> 3.3'
+  gem.add_runtime_dependency     'ebnf',            '~> 2.5'
+  gem.add_runtime_dependency     'rdf',             '~> 3.3'
+  gem.add_runtime_dependency     'sparql',          '~> 3.3'
   gem.add_runtime_dependency     'sxp',             '~> 2.0'
 
+  gem.add_development_dependency 'getoptlong',      '~> 0.2'
   gem.add_development_dependency 'json-ld',         '~> 3.3'
   gem.add_development_dependency 'rdf-spec',        '~> 3.3'
   gem.add_development_dependency 'rdf-isomorphic',  '~> 3.3'