The most appropriate step for an AML compliance officer to take upon receiving notice of government update including the names of the latest terrorists sanctioned by the United Nations Security Council is to update the monitoring software containing sanctioned persons. This is because the AML compliance officer is responsible for ensuring that the financial institution does not engage in any transactions or business relationships with individuals or entities that are subject to sanctions, as this could expose the institution to legal, regulatory, and reputational risks. By updating the monitoring software, the AML compliance officer can ensure that the institution's screening and filtering systems are up to date and can flag any potential matches or hits with the sanctioned persons. This would also enable the AML compliance officer to take appropriate actions, such as blocking or freezing funds, reporting to the relevant authorities, and conducting further due diligence, if necessary.
:
Anti-Money Laundering (AML) | FINRA.org, Overview.
AML Compliance Officer and Their Responsibilities - Tookitaki, Role and Responsibilities of an AML Compliance Officer.
What is an AML Compliance Officer? - Sanction Scanner, Communicate openly with the company's internal management team.
Guidance on Existing AML Program Rule Compliance ... - FinCEN.gov, Financial Institutions Toll-Free Hotline.

A U.S. bank must block or reject an international funds transfer when there is an OFAC designated party to the transaction, regardless of the beneficiary or the correspondent bank. This is because the U.S. bank is prohibited from dealing with any person orentity that is on the Specially Designated Nationals and Blocked Persons List (SDN List) or subject to any other OFAC sanctions program1. The SDN List includes individuals, groups, and entities, such as terrorists and narcotics traffickers, that are designated under programs that are not country-specific2. The U.S. bank must also report any blocked or rejected transactions to OFAC within 10 business days3.: 1: FFIEC BSA/AML Office of Foreign Assets Control - Office of Foreign ... 2: Specially Designated Nationals And Blocked Persons List (SDN) Human ... 3: [Reporting Blocked Transactions | Office of Foreign Assets Control]

One of the key components of an effective anti-money laundering (AML) program is to implement adequate customer due diligence (CDD) measures for new accounts. This includes verifying the identity of the party opening the account, determining the beneficial owner(s) of the account, and seeking to determine the source of deposited funds. These measures help the financial institution (FI) to understand the nature and purpose of the customer relationship, assess the risk profile of the customer, and detect and report any suspicious or unusual activity. Documenting the identity of the party opening the account and the beneficial owner(s) of the account also helps the FI to comply with the record-keeping and reporting requirements of the AML laws and regulations, and to cooperate with the authorities in case of investigations or inquiries. Seeking to determine the source of deposited funds helps the FI to prevent the introduction of illicit funds into the financial system, and to identify any discrepancies or inconsistencies between the customer's profile and activity.
:
1: FATF Guidance for a Risk-Based Approach for the Banking Sector1
2: OCC Bulletin 2020-10: Customer Due Diligence and Bank Secrecy Act/Anti-Money Laundering Examination Procedures2
3: ACAMS Study Guide for the CAMS Certification Examination3

According to 18 U.S.C. § 1956, the money laundering statute, the property involved in a financial transaction must represent the proceeds of some form of unlawful activity, which is defined as a specified unlawful activity (SUA). SUAs include over 250 crimes in six categories, such as RICO predicate offenses, certain offenses against foreign nations, acts constituting a criminal enterprise under the Controlled Substances Act, and federal health care offenses. Therefore, in order to pursue a money laundering conviction, the government must prove that at least one SUA was committed and that the property involved in the transaction was derived from that SUA.
:
18 U.S. Code § 1956 - Laundering of monetary instruments, (a)(1) and (7).
957. Money Laundering-18 U.S.C. §§ 1956 & 1957, first paragraph.
Specified Unlawful Activities (SUA), first paragraph.

A qualified independent party/auditor is the most effective resource to evaluate the effectiveness of an anti- money laundering program. This is because an independent auditor can provide an objective and unbiased assessment of the program, identify any weaknesses or gaps, and make recommendations for improvement.
An independent auditor can also verify the compliance of the program with the relevant regulations and best practices, and test the adequacy and functionality of the internal controls, customer due diligence processes, and transaction monitoring systems. An independent auditor can also help an organization prepare for regulatory examinations and audits, and avoid potential penalties or sanctions.: = The main references for this question are the following sources:
The document titled "Frequently Asked Questions Conducting Independent Reviews of Money Services Business Anti-Money Laundering Programs" published by the Financial Crimes Enforcement Network (FinCEN) in July 2010. You can access it by clicking here.
The document titled "AML Audit: How to Effectively Assess Your Compliance Program" published by Alessa in May 2023. You can access it by clicking here.
The document titled "Mutual Evaluations" published by the Financial Action Task Force (FATF). You can access it by clicking here.